Unify some SkNx code

 - one base case and one N=1 case instead of two each (or three with doubles)
 - use SkNx_cast instead of FromBytes/toBytes
 - 4-at-a-time Sk4f::ToBytes becomes a special standalone Sk4f_ToBytes

If I did everything right, this'll be perf- and pixel- neutral.

https://gold.skia.org/search2?issue=1526523003&unt=true&query=source_type%3Dgm&master=false

BUG=skia:
CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot

Review URL: https://codereview.chromium.org/1526523003

1 files changed, 0 insertions, 15 deletions

diff --git a/tests/SkNxTest.cpp b/tests/SkNxTest.cpp
index b3e03d0a9b..754e9800b1 100644
--- a/tests/SkNxTest.cpp
+++ b/tests/SkNxTest.cpp
@@ -207,21 +207,6 @@ DEF_TEST(Sk4px_widening, r) {
     REPORTER_ASSERT(r, 0 == memcmp(&wideLoHi, &wideLoHiAlt, sizeof(wideLoHi)));
 }
 
-DEF_TEST(Sk4f_toBytes, r) {
-    uint8_t bytes[4];
-
-    // toBytes truncates, not rounds.
-    Sk4f(0.7f).toBytes(bytes);
-    REPORTER_ASSERT(r, bytes[0] == 0);
-
-    // Clamping edge cases.
-    Sk4f(-2.0f, -0.7f, 255.9f, 256.0f).toBytes(bytes);
-    REPORTER_ASSERT(r, bytes[0] == 0);
-    REPORTER_ASSERT(r, bytes[1] == 0);
-    REPORTER_ASSERT(r, bytes[2] == 255);
-    REPORTER_ASSERT(r, bytes[3] == 255);
-}
-
 DEF_TEST(SkNx_cast, r) {
     Sk4f fs(-1.7f, -1.4f, 0.5f, 1.9f);
     Sk4i is = SkNx_cast<int>(fs);