Bug 1278303 part 4 - Fix correctness issue of MCreateThis new-target operand index. r=efaust

js/src/jit/MIR.h

@@ -4765,7 +4765,7 @@ class MCreateThis
   public:
     INSTRUCTION_HEADER(CreateThis)
     TRIVIAL_NEW_WRAPPERS
-    NAMED_OPERANDS((0, getCallee), (0, getNewTarget))
+    NAMED_OPERANDS((0, getCallee), (1, getNewTarget))
 
     // Although creation of |this| modifies global state, it is safely repeatable.
     AliasSet getAliasSet() const override {