Suppress a data race in WorkerFileSystemTest.AsyncOperations...

tools/valgrind/tsan/suppressions.txt

 ############################
 # Real races in Chromium
 {
   bug_23433
   ThreadSanitizer:Race
   fun:*logging*SetMinLogLevel*
 }
 
 {
   bug_24419
@@ skipping 119 matching lines @@
   bug_72913
   ThreadSanitizer:Race
   ...
   fun:ObserverListBase*
   ...
   fun:sync_api::SyncManager::SyncInternal::*
   fun:sync_api::SyncManager::*
   fun:browser_sync::*
 }
 
+{
+  bug_78302
+  ThreadSanitizer:Race
+  fun:WebCore::WorkerScriptController::forbidExecution*
+  fun:WebCore::WorkerThread::stop*
+  fun:WebKit::WebWorkerBase::stopWorkerThread*
+  fun:WebKit::WebWorkerImpl::terminateWorkerContext*
+  fun:WebWorkerStub::OnTerminateWorkerContext*
+}
+
 ############################
 # Benign races in Chromium
 {
   bug_61179 [benign race on tracked_objects::Births]
   ThreadSanitizer:Race
   fun:tracked_objects::Births::*Birth*
 }
 
 {
   bug_62694 [benign races in Histogram in CookieMonster]
@@ skipping 342 matching lines @@
   fun:WebCore::ResourceResponseBase::~ResourceResponseBase*
   fun:WebCore::ResourceResponse::~ResourceResponse*
   ...
   fun:WebCore::DocumentLoader::~DocumentLoader*
   fun:WebKit::WebDataSourceImpl::~WebDataSourceImpl*
 }
 
 {
   bug_70085b
   ThreadSanitizer:Race
-  fun:WebCore::SecurityOrigin::~SecurityOrigin*
-  fun:WTF::ThreadSafe*<WebCore::SecurityOrigin>::deref*
+  ...
+  fun:WTF::ThreadSafeRefCounted<*>::deref*
 }