Remove stale pixel expectations

Autogenerated CL from running:

//content/test/gpu/unexpected_pass_finder.py --project chrome-unexpected-pass-data --include-internal-builders --remove-stale-expectations --narrow-semi-stale-expectation-scope --num-samples 300 --suite pixel --jobs 4 --disable-batching

Affected bugs for CL description:

R=rubber-stamper@appspot.gserviceaccount.com

Bug: 1489248
Change-Id: I953c8e1b2c7b75462ec14dc02e7efd6e4ee1debf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4987446
Auto-Submit: chrome-automated-expectation@chops-service-accounts.iam.gserviceaccount.com <chrome-automated-expectation@chops-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1216646}

content/test/gpu/gpu_tests/test_expectations/pixel_expectations.txt

@@ -408,7 +408,6 @@ crbug.com/1477318 [ mac ] Pixel_WebGLPreservedAfterTabSwitch [ RetryOnFailure ]
 
 # GL Crash on Nexus 5X causing flakes
 crbug.com/1489248 [ android android-chromium android-nexus-5x no-clang-coverage ] Pixel_Video_MP4_FourColors_Rot_90 [ RetryOnFailure ]
-crbug.com/1489248 [ android android-chromium android-nexus-5x no-clang-coverage ] Pixel_Video_MP4_Rounded_Corner [ RetryOnFailure ]
 
 # Fails almost consistently, but likely to pass when run on its own in the retry.
 crbug.com/1484212 [ win debug nvidia ] Pixel_WebGL2_BlitFramebuffer_Result_Displayed [ RetryOnFailure ]