Bug 1172895: Raise the stack size limit for JS helper threads; r=bhackett

--HG--
extra : rebase_source : 68e54a51d1d2dd2571456648d982e1b2bcad47dd
extra : amend_source : 9dcced8f16960884fdf02f5926688060789ad2d1

js/src/vm/HelperThreads.cpp

@@ -434,8 +434,8 @@ js::EnqueuePendingParseTasksAfterGC(JSRuntime* rt)
     HelperThreadState().notifyAll(GlobalHelperThreadState::PRODUCER);
 }
 
-static const uint32_t kDefaultHelperStackSize = 512 * 1024;
-static const uint32_t kDefaultHelperStackQuota = 450 * 1024;
+static const uint32_t kDefaultHelperStackSize = 2048 * 1024;
+static const uint32_t kDefaultHelperStackQuota = 1800 * 1024;
 
 // TSan enforces a minimum stack size that's just slightly larger than our
 // default helper stack size.  It does this to store blobs of TSan-specific