Put RegExp js code in strict mode

src/js/regexp.js was one of the few files that was left in sloppy
mode. The ES2017 draft specification requires that writes to
lastIndex throw when the property is non-writable, and test262
tests enforce this behavior. This patch puts that file in strict
mode.

BUG=v8:4504
R=yangguo@chromium.org
LOG=Y

Review URL: https://codereview.chromium.org/1776883005

Cr-Commit-Position: refs/heads/master@{#34801}

src/js/regexp.js

@@ -4,6 +4,8 @@
 
 (function(global, utils) {
 
+'use strict';
+
 %CheckIsBootstrapping();
 
 // -------------------------------------------------------------------

test/mjsunit/regexp-lastIndex.js

+// Copyright 2016 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.
+
+// lastIndex is set according to funny rules. It is typically set only
+// for global or sticky RegExps, but on a failure to find a match, it is
+// set unconditionally. If a set fails, then it acts as if in strict mode
+// and throws.
+
+var re = /x/;
+Object.defineProperty(re, 'lastIndex', {writable: false});
+assertThrows(() => re.exec(""), TypeError);
+assertEquals(["x"], re.exec("x"));
+
+var re = /x/y;
+Object.defineProperty(re, 'lastIndex', {writable: false});
+assertThrows(() => re.exec(""), TypeError);
+assertThrows(() => re.exec("x"), TypeError);

test/test262/test262.status

@@ -110,10 +110,6 @@
   'built-ins/RegExp/prototype/exec/get-sticky-err': [FAIL],
   'built-ins/RegExp/prototype/test/get-sticky-err': [FAIL],
 
-  # https://code.google.com/p/v8/issues/detail?id=4504
-  'built-ins/RegExp/prototype/exec/y-fail-lastindex-no-write': [PASS, FAIL],
-  'built-ins/RegExp/prototype/test/y-fail-lastindex-no-write': [PASS, FAIL],
-
   # https://code.google.com/p/v8/issues/detail?id=4305
   # SKIP rather than FAIL some tests, as they may check for an exception which
   # happens to be thrown for some other reason (e.g,

test/webkit/fast/regex/lastIndex-expected.txt

@@ -42,10 +42,10 @@ PASS var re = Object.defineProperty(/x/, 'lastIndex', {value:42}); re.lastIndex
 PASS Object.defineProperty(Object.defineProperty(/x/, 'lastIndex', {writable:false}), 'lastIndex', {writable:true}); true threw exception TypeError: Cannot redefine property: lastIndex.
 PASS Object.defineProperty(Object.defineProperty(/x/, 'lastIndex', {writable:false}), 'lastIndex', {value:42}); true threw exception TypeError: Cannot redefine property: lastIndex.
 PASS Object.defineProperty(Object.defineProperty(/x/, 'lastIndex', {writable:false}), 'lastIndex', {value:0}); true is true
-PASS Object.defineProperty(/x/, 'lastIndex', {writable:false}).exec('') is null
+FAIL Object.defineProperty(/x/, 'lastIndex', {writable:false}).exec('') should be null. Threw exception TypeError: Cannot assign to read only property 'lastIndex' of object '[object RegExp]'
 PASS Object.defineProperty(/x/, 'lastIndex', {writable:false}).exec('x') is ["x"]
-FAIL Object.defineProperty(/x/g, 'lastIndex', {writable:false}).exec('') should throw an exception. Was null.
-FAIL Object.defineProperty(/x/g, 'lastIndex', {writable:false}).exec('x') should throw an exception. Was x.
+PASS Object.defineProperty(/x/g, 'lastIndex', {writable:false}).exec('') threw exception TypeError: Cannot assign to read only property 'lastIndex' of object '[object RegExp]'.
+PASS Object.defineProperty(/x/g, 'lastIndex', {writable:false}).exec('x') threw exception TypeError: Cannot assign to read only property 'lastIndex' of object '[object RegExp]'.
 PASS var re = /x/; Object.freeze(re); Object.isFrozen(re); is true
 PASS successfullyParsed is true