Remove (again) browser_tests as isolated on Windows.
Remove (again) browser_tests as isolated on Windows.

Add MAC_ISOLATE_ENABLED_TESTS to simplify the diff once we start adding test
there. Added a comment about what needs to be fixed first.

TBR=csharp@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/13860009

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@195803 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build