Remove support for legacy const, part 1

test/mjsunit/regress/regress-4576.js

Index: test/mjsunit/regress/regress-4576.js
diff --git a/test/mjsunit/regress/regress-4576.js b/test/mjsunit/regress/regress-4576.js
deleted file mode 100644
index c55c69580a5843bb85c84cb76f7f3a197d58ca12..0000000000000000000000000000000000000000
--- a/test/mjsunit/regress/regress-4576.js
+++ /dev/null
@@ -1,12 +0,0 @@
-// Copyright 2015 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// Flags: --harmony-sloppy --legacy-const
-
-// Should trigger a runtime error, not an early error.
-function f() {
-  const x;
-  var x;
-}
-assertThrows(f, SyntaxError);