Bug 968390 - Mark Math.pow as safe for parallel execution. r=luke

js/src/jit/ParallelSafetyAnalysis.cpp

@@ -278,8 +278,8 @@ class ParallelSafetyVisitor : public MInstructionVisitor
     UNSAFE_OP(SetDOMProperty)
     UNSAFE_OP(NewStringObject)
     UNSAFE_OP(Random)
-    UNSAFE_OP(Pow)
-    UNSAFE_OP(PowHalf)
+    SAFE_OP(Pow)
+    SAFE_OP(PowHalf)
     UNSAFE_OP(RegExpTest)
     UNSAFE_OP(RegExpExec)
     UNSAFE_OP(RegExpReplace)