Enable Pixel video tests on Mac Pro FYI Release bot.

Enable 6 pixel video tests on Mac Pro FYI Release (AMD) bot since the
test was fixed in CL -
https://chromium-review.googlesource.com/c/chromium/src/+/1699401.

Bug: 925744,911413
Change-Id: I62bf4f3beb4337d2eb84692c96ac30c3952322a1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1710881
Commit-Queue: vikas soni <vikassoni@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680086}

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

@@ -136,14 +136,6 @@ crbug.com/883500 [ android-chromium no-use-vulkan qualcomm-adreno-(tm)-418 ] Pix
 # context loss which results in hardware decoder loss.
 crbug.com/580386 [ android ] Pixel_Video_Context_Loss_MP4 [ Skip ]
 
-# Fails on Mac Pro FYI Release (AMD)
-crbug.com/925744 [ mac amd-0x679e ] Pixel_Video_MP4 [ Skip ]
-crbug.com/925744 [ mac amd-0x679e ] Pixel_Video_Context_Loss_MP4 [ Skip ]
-crbug.com/911413 [ mac amd-0x679e ] Pixel_Video_MP4_FourColors_Aspect_4x3 [ Skip ]
-crbug.com/911413 [ mac amd-0x679e ] Pixel_Video_MP4_FourColors_Rot_90 [ Skip ]
-crbug.com/911413 [ mac amd-0x679e ] Pixel_Video_MP4_FourColors_Rot_180 [ Skip ]
-crbug.com/911413 [ mac amd-0x679e ] Pixel_Video_MP4_FourColors_Rot_270 [ Skip ]
-
 # Fails on multiple Android devices.
 crbug.com/927107 [ android no-skia-renderer ] Pixel_CSS3DBlueBox [ Failure ]