gpu: Suppress more failing webgl tests on Mac Retina NVIDIA.

This marks a few tests as RetryOnFailure which are flaky on this bot.

R=kbr@chromium.org

Bug: 1037650
Change-Id: I08d873bc0a4f579ebba27edc3c34adaf21b8f477
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1981111
Commit-Queue: Khushal <khushalsagar@chromium.org>
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Auto-Submit: Khushal <khushalsagar@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#727275}

content/test/gpu/gpu_tests/test_expectations/webgl2_conformance_expectations.txt

@@ -442,6 +442,8 @@ crbug.com/1027776 [ mac nvidia-0xfe9 ] conformance2/textures/canvas_sub_rectangl
 crbug.com/1027776 [ mac nvidia-0xfe9 ] conformance2/textures/canvas_sub_rectangle/tex-2d-rgb5_a1-rgba-unsigned_byte.html [ Failure ]
 crbug.com/1027776 [ mac nvidia-0xfe9 ] conformance/textures/canvas_sub_rectangle/tex-2d-rgba-rgba-unsigned_byte.html [ Failure ]
 crbug.com/1027776 [ mac nvidia-0xfe9 ] conformance2/textures/canvas_sub_rectangle/tex-2d-rg32f-rg-float.html [ Failure ]
+crbug.com/1037650 [ mac nvidia-0xfe9 ] conformance2/textures/canvas_sub_rectangle/tex-2d-rgb8ui-rgb_integer-unsigned_byte.html [ RetryOnFailure ]
+crbug.com/1037650 [ mac nvidia-0xfe9 ] conformance2/textures/canvas_sub_rectangle/tex-2d-r11f_g11f_b10f-rgb-half_float.html [ RetryOnFailure ]
 
 # Mac AMD
 # TODO(kbr): uncomment the following two exepectations after test