Revert "Suppress failling WebGL test on Linux Nvidia"

This reverts commit e73c82bc.

Reason for revert: source problem looks fixed.

Original change's description:
> Suppress failling WebGL test on Linux Nvidia
> 
> WebglConformance_conformance2_context_methods_2 is failing sometimes on Linux Nvidia with
> a GPU crash. Mark the test as flaky.
> 
> BUG=906212
> TBR=kbr@chromium.org
> 
> Change-Id: I86bea7e01fde6b26b25d7fa27c8a9f41e5be9df7
> Reviewed-on: https://chromium-review.googlesource.com/c/1340948
> Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
> Commit-Queue: Robert Kroeger <rjkroege@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#609037}

TBR=rjkroege@chromium.org,kbr@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 906212, 905519
Change-Id: Ie5918918c972ac81fd0d48e9ac285c0a705a91d8
Reviewed-on: https://chromium-review.googlesource.com/c/1342500Reviewed-by: Antoine Labour <piman@chromium.org>
Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Commit-Queue: Antoine Labour <piman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609357}

content/test/gpu/gpu_tests/webgl_conformance_expectations.py

@@ -640,8 +640,6 @@ class WebGLConformanceExpectations(GpuTestExpectations):
     self.Flaky('conformance/textures/image/' +
                'tex-2d-rgb-rgb-unsigned_byte.html',
                ['linux', 'nvidia'], bug=596622)
-    self.Flaky('conformance2/context/methods-2.html',
-               ['linux', 'nvidia'], bug=906212)
 
     # NVIDIA P400 OpenGL
     self.Fail('conformance/limits/gl-max-texture-dimensions.html',