Revert of [regexp] Remove remainder of native RegExpExecStub

src/code-factory.cc

Index: src/code-factory.cc
diff --git a/src/code-factory.cc b/src/code-factory.cc
index 49dd7c7653e4ba88bbeaa972cb702a389136453b..71fbb1dbab93363ab2650bb8c53f3a5db12cbddb 100644
--- a/src/code-factory.cc
+++ b/src/code-factory.cc
@@ -229,6 +229,12 @@
 Callable CodeFactory::NumberToString(Isolate* isolate) {
   NumberToStringStub stub(isolate);
   return make_callable(stub);
+}
+
+// static
+Callable CodeFactory::RegExpExec(Isolate* isolate) {
+  RegExpExecStub stub(isolate);
+  return Callable(stub.GetCode(), stub.GetCallInterfaceDescriptor());
 }
 
 // static