Set RetryOnFailure for Pixel_OffscreenCanvasIBRCWebGLHighPerfWorker

Pixel_OffscreenCanvasIBRCWebGLHighPerfWorker is set to retry on failure
on mac intel-0xd26 because of flakiness.

TBR=kbr@chromium.org

Bug: chromium:1069339
Change-Id: I92875215b66998b33504d2bc5068ef14b0d3690e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2145566
Commit-Queue: Behdad Bakhshinategh <behdadb@chromium.org>
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758254}

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

@@ -214,6 +214,7 @@ crbug.com/1048892 [ mac nvidia ] Pixel_OffscreenCanvasIBRCWebGLHighPerfWorker [
 crbug.com/1028975 [ linux ] Pixel_PrecisionRoundedCorner [ RetryOnFailure ]
 crbug.com/1028975 [ mac ] Pixel_PrecisionRoundedCorner [ RetryOnFailure ]
 crbug.com/1028975 [ win ] Pixel_PrecisionRoundedCorner [ RetryOnFailure ]
+crbug.com/1069339 [ mac intel-0xd26 ] Pixel_OffscreenCanvasIBRCWebGLHighPerfWorker [ RetryOnFailure ]
 
 # VP9 appears to not recover correctly after GPU process crashes on Windows.
 crbug.com/1033982 [ win nvidia ] Pixel_Video_Context_Loss_VP9 [ RetryOnFailure ]