aura: Reenable PPAPITest.FLAKY_FlashFullscreen.
aura: Reenable PPAPITest.FLAKY_FlashFullscreen.

This test looks like it's passing now.

BUG=104384
TEST=ran the test locally a few times on an aura build and didn't see any failures


Review URL: http://codereview.chromium.org/8758027

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@113422 0039d316-1c4b-4281-b951-d872f2087c98

ropik/chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,adobe/chromium,ropik/chromium,gavinp/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,gavinp/chromium,ropik/chromium,yitian134/chromium,gavinp/chromium,gavinp/chromium,ropik/chromium,ropik/chromium,yitian134/chromium,gavinp/chromium,yitian134/chromium,adobe/chromium,yitian134/chromium