Suppress flaky dEQP-GLES3 test on Win7 NVIDIA D3D11

dEQP-GLES3.functional.rasterization.flatshading.triangles

Bug: angleproject:4070
Change-Id: I8bdba9d1b9d3c04df42a6c90fa106cf7e8b1a018
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1890729
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>

Author: y-novikov

src/tests/deqp_support/deqp_gles3_test_expectations.txt

@@ -103,6 +103,9 @@
 2222 D3D11 NVIDIA : dEQP-GLES3.functional.texture.mipmap.cube.min_lod.linear_nearest = FAIL
 2222 D3D11 NVIDIA : dEQP-GLES3.functional.texture.mipmap.cube.min_lod.nearest_nearest = FAIL
 
+// Flaky on Win7 D3D11 NVIDIA
+4070 WIN7 D3D11 NVIDIA : dEQP-GLES3.functional.rasterization.flatshading.triangles = FAIL
+
 // Failing everywhere
 2322 : dEQP-GLES3.functional.shaders.metamorphic.* = FAIL