[builtins] Add support for JS builtins written in TurboFan.

src/runtime/runtime-maths.cc

Index: src/runtime/runtime-maths.cc
diff --git a/src/runtime/runtime-maths.cc b/src/runtime/runtime-maths.cc
index 8a43c2758eb2c0051a3b3be7dbdb990ab57ef24b..889a016b2e3a65f633fdbcb6ca6e160290c70a66 100644
--- a/src/runtime/runtime-maths.cc
+++ b/src/runtime/runtime-maths.cc
@@ -214,17 +214,6 @@ RUNTIME_FUNCTION(Runtime_RoundNumber) {
 }
 
 
-RUNTIME_FUNCTION(Runtime_MathSqrt) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 1);
-  isolate->counters()->math_sqrt_runtime()->Increment();
-
-  CONVERT_DOUBLE_ARG_CHECKED(x, 0);
-  lazily_initialize_fast_sqrt(isolate);
-  return *isolate->factory()->NewNumber(fast_sqrt(x, isolate));
-}
-
-
 RUNTIME_FUNCTION(Runtime_GenerateRandomNumbers) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);