Update webkit status for failing test

Review-Url: https://codereview.chromium.org/2266813003
Cr-Commit-Position: refs/heads/master@{#38780}

test/webkit/webkit.status

@@ -116,6 +116,12 @@
   'dfg-int-overflow-in-loop': [SKIP],
 }],  # variant == ignition_turbofan and msan
 
+##############################################################################
+['arch == arm64 and msan', {
+  # Stack size too large with masm on Arm64.
+  'excessive-comma-usage': [SKIP],
+}],  # arch == arm64 and msan
+
 ##############################################################################
 ['gcov_coverage', {
   # Tests taking too long or getting too large call stacks.