media/gpu/vda_tests: Increase the time out in FlushAtEndOfStream

This increases the test case timeout only in FlushAtEndOfStream. We
hit the timeout in video.ChromeStackDecoderVerification with a 4k
long video because mapping VA surface on some intel devices is very
slow. This mitigate the issue by increasing the timeout to 90 seconds
if a video resolution is more than 1080p.

Bug: 230378122
Test: video.ChromeStackDecoderVerification.h264_4k_files_from_bugs* on octopus
Change-Id: I81ca6c26eaa2e94d54149d39503b46c93a4458ce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4342477


Reviewed-by: Miguel Casas-Sanchez <mcasas@chromium.org>
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1118448}