Removing SwiftShader tests on Mac

content/test/gpu/generate_buildbot_json.py

Index: content/test/gpu/generate_buildbot_json.py
diff --git a/content/test/gpu/generate_buildbot_json.py b/content/test/gpu/generate_buildbot_json.py
index 48e817708036675445e381b242a1f741cdc8eb01..9dba4daf2fd26557d4e16577ff4a1f6f6700f80e 100755
--- a/content/test/gpu/generate_buildbot_json.py
+++ b/content/test/gpu/generate_buildbot_json.py
@@ -1111,6 +1111,7 @@ COMMON_GTESTS = {
         'fyi_only': True,
         # Run this on the optional tryservers.
         'run_on_optional': True,
+        'os_types': ['win', 'linux'],
       },
     ],
   },