Mark 2 WebGL tests Flaky

conformance/rendering/gl-scissor-fbo-test.html
deqp/data/gles2/shaders/swizzles.html
on Win NVIDIA Passthrough Vulkan Debug.

TBR=kbr@chromium.org

Bug: angleproject:2939, angleproject:2940
Change-Id: I8b388eb464b42def465c231d5986852a6517e19a
Reviewed-on: https://chromium-review.googlesource.com/c/1305237Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603561}

content/test/gpu/gpu_tests/webgl_conformance_expectations.py

@@ -564,6 +564,9 @@ class WebGLConformanceExpectations(GpuTestExpectations):
         ['win', 'passthrough', 'vulkan', 'nvidia'], bug=2918) # ANGLE bug ID
     self.Fail('conformance/context/premultiplyalpha-test.html',
         ['win', 'passthrough', 'vulkan', 'nvidia'], bug=2922) # ANGLE bug ID
+    self.Flaky('conformance/rendering/gl-scissor-fbo-test.html',
+        ['win', 'passthrough', 'vulkan', 'nvidia', 'debug'],
+        bug=2939) # ANGLE bug ID
     self.Fail('conformance/textures/misc/texture-size.html',
         ['win', 'passthrough', 'vulkan', 'nvidia'], bug=2915) # ANGLE bug ID
     self.Fail('conformance/textures/misc/texture-size-cube-maps.html',
@@ -572,6 +575,9 @@ class WebGLConformanceExpectations(GpuTestExpectations):
         ['win', 'passthrough', 'vulkan', 'nvidia'], bug=2915) # ANGLE bug ID
     self.Fail('deqp/data/gles2/shaders/conversions.html',
         ['win', 'passthrough', 'vulkan', 'nvidia'], bug=2926) # ANGLE bug ID
+    self.Flaky('deqp/data/gles2/shaders/swizzles.html',
+        ['win', 'passthrough', 'vulkan', 'nvidia', 'debug'],
+        bug=2940) # ANGLE bug ID
 
     # Vulkan / Win / Intel / Passthough command decoder
     self.Fail('conformance/rendering/clipping-wide-points.html',