Limit all platforms to one GM process
Limit all platforms to one GM process

git-svn-id: 32fc27f4dcfb6c0385cd9719852b95fe6680452d@6176 2bbb7eff-a529-9590-31e7-b0007b416f81

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot