Fix tests in //api_proto on Windows (#610)
Fix tests in //api_proto on Windows (#610)

Fix the Starlark rule generating
//api_proto:api.gen.pb.go_checkshtest so it works
on Windows, where a runfiles tree is not
available.

To fix, the generated shell script now uses the
Bash runfiles library to locate the files to
compare.

See https://github.com/bazelbuild/bazel/issues/5508
bazelbuild/buildtools,bazelbuild/buildtools,bazelbuild/buildtools,bazelbuild/buildtools,bazelbuild/buildtools