Added sqrt and pow for arm and x64 - to fix build failures.

src/x64/codegen-x64.h

Index: src/x64/codegen-x64.h
===================================================================
--- src/x64/codegen-x64.h	(revision 4053)
+++ src/x64/codegen-x64.h	(working copy)
@@ -576,12 +576,15 @@
   void GenerateNumberToString(ZoneList<Expression*>* args);
 
   // Fast support for Math.pow().
-  void GeneratePow(ZoneList<Expression*>* args);
+  void GenerateMathPow(ZoneList<Expression*>* args);
 
   // Fast call to math functions.
   void GenerateMathSin(ZoneList<Expression*>* args);
   void GenerateMathCos(ZoneList<Expression*>* args);
 
+  // Fast case for sqrt
+  void GenerateMathSqrt(ZoneList<Expression*>* args);
+
 // Simple condition analysis.
   enum ConditionAnalysis {
     ALWAYS_TRUE,