[sheriff] Disable PNACL tests on MacOS

Disable PPAPINaClPNaClTest.* on MacOS. Tests are failing.

Tbr: bbudge@chromium.org
Bug: 1076806
Change-Id: I23b2c72b88e9f56c8f3f7c59b6f31e101d2b91ef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2548343Reviewed-by: Nina Satragno <nsatragno@chromium.org>
Commit-Queue: Nina Satragno <nsatragno@chromium.org>
Cr-Commit-Position: refs/heads/master@{#829003}

chrome/test/ppapi/ppapi_browsertest.cc

@@ -127,8 +127,8 @@ using content::RenderViewHost;
 
 #define MAYBE_PPAPI_NACL(test_name) test_name
 #if defined(OS_WIN) || defined(OS_LINUX) || defined(OS_CHROMEOS) || \
-    defined(ADDRESS_SANITIZER)
-// http://crbug.com/633067, http://crbug.com/727989
+    defined(OS_MACOSX) || defined(ADDRESS_SANITIZER)
+// http://crbug.com/633067, http://crbug.com/727989, http://crbug.com/1076806
 #define MAYBE_PPAPI_PNACL(test_name) DISABLED_##test_name
 #else
 #define MAYBE_PPAPI_PNACL(test_name) test_name