Revert of Build browser tests on all gpu release bots (patchset #1 id:1 of https://codereview.chromium.org/2841833003/ )

Reason for revert:
I don't think this CL is still needed after my fix for crbug.com/714976.

Original issue's description:
> Build browser tests on all gpu release bots
>
> Work-around as browser_tests are erroneously not rebuilt properly on
> gpu bots.
>
> BUG=chromium:714976
> TBR=kbr@chromium.org,fjhenigman@chromium.org
> CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.android:android_optional_gpu_tests_rel;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
> NOTRY=true
>
> Review-Url: https://codereview.chromium.org/2841833003
> Cr-Commit-Position: refs/heads/master@{#467292}
> Committed: https://chromium.googlesource.com/chromium/src/+/1d0ceecfb8153cce088d62bf28d9c94c6601de91

TBR=fjhenigman@chromium.org,kbr@chromium.org,hablich@chromium.org,phajdan.jr@chromium.org,machenbach@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=chromium:714976

Review-Url: https://codereview.chromium.org/2846883004
Cr-Original-Commit-Position: refs/heads/master@{#467921}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: a5ab58152fbb8f93dc9653f4ecce0d467fe6bf78
2 files changed