Bug 1252693 - Assert that we do not tenure into an OMT Zone; r=sfink

--HG--
extra : rebase_source : 668adb69bee704bb2cd9e68bb12b391e1a04a7d2

js/src/gc/Marking.cpp

@@ -2110,6 +2110,7 @@ JSObject*
 js::TenuringTracer::moveToTenured(JSObject* src)
 {
     MOZ_ASSERT(IsInsideNursery(src));
+    MOZ_ASSERT(!src->zone()->usedByExclusiveThread);
 
     AllocKind dstKind = src->allocKindForTenure(nursery());
     Zone* zone = src->zone();