Revert "Enable jpeg_decode_accelerator_unittest in chromiumos_preflight"

This reverts commit 58e1347031d3d01dd2671cb5933cb9323702a3a7.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 588635 as the
culprit for failures in the build cycles as shown on:
https://findit-for-me.appspot.com/waterfall/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyRAsSDVdmU3VzcGVjdGVkQ0wiMWNocm9taXVtLzU4ZTEzNDcwMzFkM2QwMWRkMjY3MWNiNTkzM2NiOTMyMzcwMmEzYTcM

Sample Failed Build: https://ci.chromium.org/buildbot/chromium/win-rel/2001

Sample Failed Step: compile

Original change's description:
> Enable jpeg_decode_accelerator_unittest in chromiumos_preflight
> 
> jpeg_decode_accelerator_unittest is compiled and run on the CrOs
> autotest infra, but is not compiled on the bots, when it possibly
> should. This CL adds that target to the chromiumos_preflight of
> the top level BUILD.gn.
> 
> Bug: 732531, 877694
> 
> Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
> Change-Id: Iee1c95a4c0c12d3a0e55451447d6d862e1cb1484
> Reviewed-on: https://chromium-review.googlesource.com/1199580
> Reviewed-by: Ben Pastene <bpastene@chromium.org>
> Reviewed-by: Dan Sanders <sandersd@chromium.org>
> Reviewed-by: John Budorick <jbudorick@chromium.org>
> Commit-Queue: Miguel Casas <mcasas@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#588635}

Change-Id: I0092e01151c3e9700ef64be7646849ff90066b01
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 732531, 877694
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Reviewed-on: https://chromium-review.googlesource.com/1204599
Cr-Commit-Position: refs/heads/master@{#588642}

• BUILD.gn[diff]
• media/gpu/BUILD.gn[diff]