Port and integrate the irregexp engine from V8

tests/language/regex/regress-regexp-codeflush_test.dart

+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'util.dart';
+import 'package:expect/expect.dart';
+
+void main() {
+  // Flags: --gc_global
+
+  // Regression test for regexp that has multiple matches and which
+  // internally calls RegExpImpl::IrregexpExecOnce more than once without
+  // ensuring that the regexp is compiled.
+  // This can create a crash if the code was exchanged with the sweep
+  // generation (for code flushing support) in GC durring the matching.
+
+  var re = new RegExp('(s)');
+
+  dynamic foo(Match m) {
+    return "42";
+  }
+
+  // Run enough times to get a number of GC's (all mark sweep because of the
+  // --gc_global) flag.
+  for ( var i = 0; i < 10; i++) {
+    // Make a long string with plenty of matches for re.
+    var x = "s foo s bar s foo s bar s";
+    x = x + x;
+    x = x + x;
+    x = x + x;
+    x = x + x;
+    x = x + x;
+    x = x + x;
+    x = x + x;
+    x.replaceAllMapped(re, foo);
+  }
+}