Revert "Update clang linux to release_40"

This reverts commit a08104abf2850546d97c5d33f5fb5fabedf45466.

Reason for revert: MSAN's failing immediately, and ASAN is catching a new leak:

==20306==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 4112 byte(s) in 257 object(s) allocated from:
    #0 0x138828b  (/b/s/w/irNps76D/out/Release/dm+0x138828b)
    #1 0x2c07b76  (/b/s/w/irNps76D/out/Release/dm+0x2c07b76)



Original change's description:
> Update clang linux to release_40
> 
> Bug: skia:
> Change-Id: Ibe2406592024a4eb20b278ad189d3abddec129d9
> Reviewed-on: https://skia-review.googlesource.com/11285
> Reviewed-by: Mike Klein <mtklein@chromium.org>
> Commit-Queue: Mike Klein <mtklein@chromium.org>
> 

TBR=mtklein@chromium.org,mtklein@google.com,kjlubick@google.com,reviews@skia.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: I178c129cf19ed38f0a91ea3eea583643daadc2c7
Reviewed-on: https://skia-review.googlesource.com/11288
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>

3 files changed, 24 insertions, 24 deletions

diff --git a/infra/bots/assets/clang_linux/VERSION b/infra/bots/assets/clang_linux/VERSION
index 301160a930..bf0d87ab1b 100644
--- a/infra/bots/assets/clang_linux/VERSION
+++ b/infra/bots/assets/clang_linux/VERSION
@@ -1 +1 @@
-8
\ No newline at end of file
+4
\ No newline at end of file
diff --git a/infra/bots/assets/clang_linux/create.py b/infra/bots/assets/clang_linux/create.py
index f7a4a07f07..a7c2484433 100755
--- a/infra/bots/assets/clang_linux/create.py
+++ b/infra/bots/assets/clang_linux/create.py
@@ -15,7 +15,7 @@ import subprocess
 import tempfile
 
 REPO = "https://llvm.googlesource.com/"
-BRANCH = "release_40"
+BRANCH = "release_39"
 
 def create_asset(target_dir):
   # Build Clang, lld, compiler-rt (sanitizer support) and libc++.
diff --git a/infra/bots/tasks.json b/infra/bots/tasks.json
index 60a665d046..734274193f 100644
--- a/infra/bots/tasks.json
+++ b/infra/bots/tasks.json
@@ -2712,7 +2712,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dimensions": [
@@ -2745,7 +2745,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dimensions": [
@@ -2778,7 +2778,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dimensions": [
@@ -2811,7 +2811,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         },
         {
           "name": "skia/bots/linux_vulkan_sdk",
@@ -2849,7 +2849,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dimensions": [
@@ -2882,7 +2882,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dimensions": [
@@ -2915,7 +2915,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dimensions": [
@@ -2948,7 +2948,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dimensions": [
@@ -2981,7 +2981,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dimensions": [
@@ -3014,7 +3014,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         },
         {
           "name": "skia/bots/linux_vulkan_sdk",
@@ -6512,7 +6512,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [
@@ -6567,7 +6567,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [
@@ -6672,7 +6672,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [
@@ -6777,7 +6777,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [
@@ -6831,7 +6831,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [
@@ -12382,7 +12382,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [
@@ -12437,7 +12437,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [
@@ -12542,7 +12542,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [
@@ -12647,7 +12647,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [
@@ -12702,7 +12702,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [
@@ -12756,7 +12756,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [
@@ -12810,7 +12810,7 @@
         {
           "name": "skia/bots/clang_linux",
           "path": "clang_linux",
-          "version": "version:8"
+          "version": "version:4"
         }
       ],
       "dependencies": [