Updates the ruby generator RubyAsType to correctly account for underscores in packages

Prior to this change, when the ruby generator tried to reference an entity that was not part of the same package
(or a direct parent package) and the package contains underscores,
the result would simply uppercase the first character.
It should however uppercase each letter that proceeds an underscore and remove underscores.

i.e.

```
package my_package.service;

import "my_package/data.proto";

service MyService {
  rpc Test (data.Request) returns data.Response {}
}
```

Was

```ruby
   # ...
   rpc :Test, My_package::Data::REquest, My_package::Data::Response
   # ...
```

Should be:

```ruby
   # ...
   rpc :Test, MyPackage::Data::REquest, My_package::Data::Response
   # ...
```

1 files changed, 3 insertions, 0 deletions

diff --git a/tools/run_tests/helper_scripts/run_ruby.sh b/tools/run_tests/helper_scripts/run_ruby.sh
index 4bd7d743c1..aefdc6fc61 100755
--- a/tools/run_tests/helper_scripts/run_ruby.sh
+++ b/tools/run_tests/helper_scripts/run_ruby.sh
@@ -18,4 +18,7 @@ set -ex
 # change to grpc repo root
 cd $(dirname $0)/../../..
 
+# build grpc_ruby_plugin
+make grpc_ruby_plugin -j8
+
 rake