[regexp] Migrate constructor and compile to CSA

src/regexp/regexp-utils.cc

Index: src/regexp/regexp-utils.cc
diff --git a/src/regexp/regexp-utils.cc b/src/regexp/regexp-utils.cc
index 62daf3f1d518b5e024aa3e043b4703dc169b17c8..f6ef076f2c38b781f58d4589e94801ce64130562 100644
--- a/src/regexp/regexp-utils.cc
+++ b/src/regexp/regexp-utils.cc
@@ -118,12 +118,6 @@ Maybe<bool> RegExpUtils::IsRegExp(Isolate* isolate, Handle<Object> object) {
 
   Handle<JSReceiver> receiver = Handle<JSReceiver>::cast(object);
 
-  if (isolate->regexp_function()->initial_map() == receiver->map()) {
-    // Fast-path for unmodified JSRegExp instances.
-    // TODO(ishell): Adapt for new fast-path logic.
-    return Just(true);
-  }
-
   Handle<Object> match;
   ASSIGN_RETURN_ON_EXCEPTION_VALUE(
       isolate, match,