Make assertion scopes thread safe.

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index 81b600574c186d8bdf76afeb2441b07a6dfc20d9..df5dbe36768c9e5d85376dc37b3fd0b8ae81db66 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -563,7 +563,7 @@ BUILTIN(ArrayPush) {
     }
 
     // Add the provided values.
-    AssertNoAllocation no_gc;
+    DisallowHeapAllocation no_gc;
     WriteBarrierMode mode = elms->GetWriteBarrierMode(no_gc);
     for (int index = 0; index < to_add; index++) {
       elms->set(index + len, args[index + 1], mode);
@@ -612,7 +612,7 @@ BUILTIN(ArrayPush) {
     }
 
     // Add the provided values.
-    AssertNoAllocation no_gc;
+    DisallowHeapAllocation no_gc;
     int index;
     for (index = 0; index < to_add; index++) {
       Object* arg = args[index + 1];