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

test/mjsunit/compiler/deopt-materialize-accumulator.js

Index: test/mjsunit/compiler/deopt-materialize-accumulator.js
diff --git a/test/mjsunit/compiler/deopt-materialize-accumulator.js b/test/mjsunit/compiler/deopt-materialize-accumulator.js
index c80e329150383ba24ab0949bbdc470576c4570bb..217de769d37f9439b9d3a6424ccb641d3d86c00c 100644
--- a/test/mjsunit/compiler/deopt-materialize-accumulator.js
+++ b/test/mjsunit/compiler/deopt-materialize-accumulator.js
@@ -34,7 +34,7 @@ var global = 3;
 function f(a) {
   // This will trigger a deopt since global was previously a SMI, with the
   // accumulator holding an unboxed double which needs materialized.
-  global = %_MathSqrt(a);
+  global = %math_sqrt(a);
 }
 %OptimizeFunctionOnNextCall(f);
 f(0.25);