Re-enable Win x64 tests as they're now disabled in code.
Re-enable Win x64 tests as they're now disabled in code.

BUG=webrtc:1458,webrtc:1459,webrtc:1460,webrtc:1461
TEST=Compiled the tests with SET GYP_DEFINES=target_arch=x64 on
Windows and executed them successfully.

Review URL: https://chromiumcodereview.appspot.com/15930011

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@203931 0039d316-1c4b-4281-b951-d872f2087c98

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