Skip flaky BlendMinMaxTest.RGBA16F/ES2_Metal.

BUG=angleproject:4185

Change-Id: I236d4372ab22e9083d00cf13fa2ad682a1d42f14
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1947447
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
diff --git a/src/tests/gl_tests/BlendMinMaxTest.cpp b/src/tests/gl_tests/BlendMinMaxTest.cpp
index a01389e..fe30dda 100644
--- a/src/tests/gl_tests/BlendMinMaxTest.cpp
+++ b/src/tests/gl_tests/BlendMinMaxTest.cpp
@@ -193,6 +193,9 @@
     // http://anglebug.com/4092
     ANGLE_SKIP_TEST_IF((IsAndroid() && IsVulkan()) || isSwiftshader());
 
+    // http://anglebug.com/4185
+    ANGLE_SKIP_TEST_IF(IsMetal());
+
     runTest(GL_RGBA16F, GL_FLOAT);
 }