Bug 1304638 - Remove redundant call to offsetForStackOperand. r=nbp

No state changes between the first and second call.

MozReview-Commit-ID: 38FooLQnn9b
Signed-off-by: Emilio Cobos Álvarez <ecoal95@gmail.com>

js/src/jsopcode.cpp

@@ -354,7 +354,7 @@ class BytecodeParser
         uint32_t offset = offsetForStackOperand(script_->pcToOffset(pc), operand);
         if (offset >= SpecialOffsets::FirstSpecialOffset)
             return nullptr;
-        return script_->offsetToPC(offsetForStackOperand(script_->pcToOffset(pc), operand));
+        return script_->offsetToPC(offset);
     }
 
   private: