Remove failed entries in GPU pixel tests

TBR=kbr@chromium.org
BUG=662498
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2599823002
Cr-Commit-Position: refs/heads/master@{#440461}
1 file changed