Remove failed gpu pixel test entries

TBR=kbr@chromium.org
BUG=655335
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/2586283002
Cr-Commit-Position: refs/heads/master@{#439512}
1 file changed