[strong] Remove all remainders of strong mode

test/mjsunit/strong/eval-direct.js

-// 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: --strong-mode
-
-// In strong mode, direct calls to eval are forbidden
-
-assertThrows("'use strong'; eval();", SyntaxError);
-assertThrows("'use strong'; (eval)();", SyntaxError);
-assertThrows("'use strong'; (((eval)))();", SyntaxError);
-assertThrows("'use strong'; eval([]);", SyntaxError);
-assertThrows("'use strong'; eval('function f() {}');", SyntaxError);
-assertThrows("'use strong'; function f() {eval()}", SyntaxError);
-
-assertDoesNotThrow("'use strong'; eval;");
-assertDoesNotThrow("'use strong'; let foo = eval; foo();");
-assertDoesNotThrow("'use strong'; (1, eval)();");
-
-// TODO(neis): The tagged template triggers %ObjectFreeze on an array, which
-// throws when trying to redefine 'length'.
-// assertDoesNotThrow("'use strong'; eval`foo`;");