Suppress WebGL Mac end2end failures.
Suppress WebGL Mac end2end failures.

WebGLCompatibilityTest.R16FTextures/ES3_OpenGL
WebGLCompatibilityTest.RG16FTextures/ES3_OpenGL
WebGLCompatibilityTest.RGB16FTextures/ES3_OpenGL
WebGLCompatibilityTest.RGBA16FTextures/ES3_OpenGL
WebGLCompatibilityTest.RGBA32FTextures/ES3_OpenGL

Bug: angleproject:5357
Change-Id: I63a98fc1dc7316db0a5203e3bc814d8751c1bf58
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2553789
Reviewed-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>
Commit-Queue: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>

ppy/angle,ppy/angle,ppy/angle,ppy/angle