Compat CTS: add a flaky test to expectations.

Change-Id: I71ac39d7b9236e582b9a1d9dad8954e46648ac0e
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/163141
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
Bot-Commit: rubber-stamper@appspot.gserviceaccount.com <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
diff --git a/webgpu-cts/compat-expectations.txt b/webgpu-cts/compat-expectations.txt
index 1596585..1b56cf6 100644
--- a/webgpu-cts/compat-expectations.txt
+++ b/webgpu-cts/compat-expectations.txt
@@ -727,3 +727,7 @@
 crbug.com/dawn/0000 webgpu:shader,execution,expression,call,builtin,fract:f32:inputSource="const";vectorize=2 [ Failure ]
 crbug.com/dawn/0000 webgpu:shader,execution,expression,call,builtin,fract:f32:inputSource="const";vectorize=3 [ Failure ]
 crbug.com/dawn/0000 webgpu:shader,execution,expression,call,builtin,fract:f32:inputSource="const";vectorize=4 [ Failure ]
+
+# Flaky on all platforms
+# KEEP
+crbug.com/dawn/0000 webgpu:shader,validation,expression,call,builtin,log:values:stage="override";type="f32" [ Failure ]