Suppress one more data race in WebKit related to WorkerThreads...

tools/valgrind/tsan/suppressions.txt

 ############################
 # Chromium
 
 {
   bug_23433
   ThreadSanitizer:Race
   fun:*logging*SetMinLogLevel*
 }
 
 {
@@ skipping 127 matching lines @@
 {
   bug_72913
   ThreadSanitizer:Race
   ...
   fun:ObserverListBase*
   fun:sync_api::SyncManager::SyncInternal::*
   fun:sync_api::SyncManager::*
   fun:browser_sync::*
 }
 
+{
+  bug_75607
+  ThreadSanitizer:Race
+  fun:WebCore::ResourceResponseBase::~ResourceResponseBase*
+  fun:WebCore::ResourceResponse::~ResourceResponse*
+  ...
+  fun:WebCore::DocumentLoader::~DocumentLoader*
+  fun:WebKit::WebDataSourceImpl::~WebDataSourceImpl*
+}
+
 ############################
 # Benign races
 {
   bug_62694 [benign races in Histogram in CookieMonster]
   ThreadSanitizer:Race
   ...
   fun:base::Histogram::*
   fun:net::CookieMonster::*
 }
 
@@ skipping 359 matching lines @@
   tsanbug_62a
   ThreadSanitizer:Race
   fun:__memset_sse2
 }
 
 {
   tsanbug_62b
   ThreadSanitizer:Race
   fun:__GI_memcpy
 }