Remove suppression for OES_fbo_render_mipmap on win passthrough

Fix in angle has been rolled in.
https://chromium.googlesource.com/chromium/src.git/+/34d9b5182ad4ee54a6fd66e6247a56e61d313e05

TBR=kbr@chromium.org

Bug: 1023747
Change-Id: I540be727d1e92978cb497fff12581a9a87f0618c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1952169Reviewed-by: Shrek Shao <shrekshao@google.com>
Commit-Queue: Shrek Shao <shrekshao@google.com>
Cr-Commit-Position: refs/heads/master@{#722729}

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

@@ -122,9 +122,6 @@ crbug.com/751849 [ win7 debug nvidia d3d11 passthrough ] conformance/extensions/
 # Win failures     #
 ####################
 
-# Failed issues
-crbug.com/1023747 [ win d3d11 passthrough ] WebglExtension_OES_fbo_render_mipmap [ Failure ]
-
 # Intel flaky issues
 crbug.com/825338 [ win intel d3d11 ] conformance/extensions/oes-texture-float-with-video.html [ RetryOnFailure ]
 crbug.com/929009 [ win intel ] conformance/glsl/misc/shader-with-non-reserved-words.html [ RetryOnFailure ]