Suppress flaky deqp/functional/gles3/shaderloop_for.html on Win NVIDIA GL

TBR=kbr

Bug: 1060024
Change-Id: Ifaa67a559d54df54749d387b73a89f258dfa35e1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2218693Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772389}

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

@@ -226,6 +226,7 @@ crbug.com/887578 [ opengl win passthrough nvidia        ] deqp/data/gles3/shader
 crbug.com/965648 [ opengl win passthrough nvidia-0x1cb3 ] deqp/functional/gles3/shaderstruct.html [ RetryOnFailure ]
 crbug.com/822733 [ opengl win nvidia-0x1cb3             ] deqp/functional/gles3/transformfeedback/* [ RetryOnFailure ]
 crbug.com/1060024 [ opengl win passthrough nvidia-0x1cb3 ] deqp/functional/gles3/shaderloop_do_while.html [ RetryOnFailure ]
+crbug.com/1060024 [ opengl win passthrough nvidia-0x1cb3 ] deqp/functional/gles3/shaderloop_for.html [ RetryOnFailure ]
 crbug.com/1060024 [ opengl win passthrough nvidia-0x1cb3 ] deqp/functional/gles3/shaderloop_while.html [ RetryOnFailure ]
 crbug.com/angleproject/4555 [ win opengl passthrough nvidia ] conformance/misc/type-conversion-test.html [ Skip ]