Lift old WebGL NV Windows expectation.

This test does not show up in the flakiness dashboard.

Test: deqp/functional/gles3/fbomultisample*
Bug: 631317
Change-Id: I1f439515b444cfe5314b36d807cc4d9b71d873e7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2371038Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800897}

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

@@ -186,7 +186,6 @@ crbug.com/angleproject/1465 [ win no-use-gl ] conformance2/glsl3/tricky-loop-con
 crbug.com/angleproject/1465 [ win d3d11 ] conformance2/glsl3/tricky-loop-conditions.html [ Failure ]
 
 # Win / NVidia
-crbug.com/631317 [ d3d11 win nvidia ] deqp/functional/gles3/fbomultisample* [ RetryOnFailure ]
 crbug.com/679639 [ d3d11 win nvidia ] conformance2/rendering/draw-with-integer-texture-base-level.html [ Failure ]
 # Flake seen once.
 crbug.com/691951 [ d3d11 win nvidia ] deqp/functional/gles3/shaderoperator/binary_operator_11.html [ RetryOnFailure ]