gpu: suppress s3tc-and-rgtc.html on mac nvidia

Mac Nvidia Retina is failing consistently on s3tc-and-rgtc.html.
Suppress the test failure.

Bug: 1153689
Change-Id: Idd1e491643ccdf37980655dc62a9e53acf44059f
TBR: kbr@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2565731Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Commit-Queue: Robert Kroeger <rjkroege@chromium.org>
Cr-Commit-Position: refs/heads/master@{#832016}

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

@@ -518,6 +518,7 @@ crbug.com/1027776 [ mac nvidia-0xfe9 ] conformance2/rendering/framebuffer-textur
 crbug.com/1037650 [ mac nvidia-0xfe9 ] conformance2/textures/canvas_sub_rectangle/* [ RetryOnFailure ]
 crbug.com/1073538 [ mac nvidia-0xfe9 ] deqp/functional/gles3/shadermatrix/div_dynamic.html [ RetryOnFailure ]
 crbug.com/1086194 [ mac nvidia-0xfe9 ] conformance/textures/canvas_sub_rectangle/* [ RetryOnFailure ]
+crbug.com/1153689 [ mac nvidia-0xfe9 ] conformance/extensions/s3tc-and-rgtc.html [ Failure ]
 
 # Mac AMD
 # AMD Radeon HD 8870M (1002:6821)

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

@@ -501,6 +501,7 @@ crbug.com/1027776 [ mac nvidia-0xfe9 ] conformance/textures/canvas_sub_rectangle
 
 # Mac / Passthrough command decoder
 crbug.com/angleproject/4986 [ mac passthrough ] conformance/textures/misc/gl-teximage.html [ Failure ]
+crbug.com/1153689 [ mac nvidia-0xfe9 passthrough ] conformance/extensions/s3tc-and-rgtc.html [ Failure ]
 
 # Mac / Passthrough command decoder / OpenGL
 crbug.com/989194 [ mac passthrough angle-opengl ] conformance/extensions/oes-texture-half-float.html [ Failure ]