[test] Skip some tests on the coverage bot.

test/webkit/webkit.status

 # Copyright 2013 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 77 matching lines @@
 ['gc_stress == True', {
   # Tests taking too long
   'fast/js/excessive-comma-usage': [SKIP]
 }],  # 'gc_stress == True'
 
 ['gc_stress == True and mode == debug', {
   # Skip tests that timeout.
 }],  # 'gc_stress == True and mode == debug'
 
 ##############################################################################
+['gcov_coverage', {
+  # Tests taking too long or getting too large call stacks.
+  'fast/js/excessive-comma-usage': [SKIP],
+  'run-json-stringify': [SKIP],
+}],  # 'gcov_coverage'
+
+##############################################################################
 ]