VM: Optimize RegExp.matchAsPrefix(...) by generating a sticky RegExp specialization.

tests/corelib/regexp/regexp_test.dart

 // Copyright (c) 2014, the Dart project authors. All rights reserved.
 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
@@ skipping 573 matching lines @@
   assertThrows(() => new RegExp('(?=*)'));
   assertThrows(() => new RegExp('(?!*)'));
 
   // Test trimmed regular expression for RegExp.test().
   assertTrue("abc".contains(new RegExp(r".*abc")));
   assertFalse("q".contains(new RegExp(r".*\d+")));
 
   // Tests skipped from V8:
   // Test that RegExp.prototype.toString() throws TypeError for
   // incompatible receivers (ES5 section 15.10.6 and 15.10.6.4).
+
+  testSticky();
 }
+
+testSticky() {
+  var re = new RegExp(r"foo.bar");
+  Expect.isNotNull(re.matchAsPrefix("foo_bar", 0));
+  Expect.isNull(re.matchAsPrefix("..foo_bar", 0));
+  Expect.isNotNull(re.matchAsPrefix("..foo_bar", 2));
+
+  re = new RegExp(r"^foo");
+  Expect.isNotNull(re.matchAsPrefix("foobar", 0));
+  Expect.isNull(re.matchAsPrefix("..foo", 0));
+  Expect.isNull(re.matchAsPrefix("..foo", 2));
+
+  re = new RegExp(r"^foo", multiLine: true);
+  Expect.isNotNull(re.matchAsPrefix("foobar", 0));
+  Expect.isNull(re.matchAsPrefix("..\nfoo", 0));
+  Expect.isNotNull(re.matchAsPrefix("..\nfoo", 3));
+  Expect.isNull(re.matchAsPrefix("..\nfoofoo", 6));
+
+  re = new RegExp(r"bar$");
+  Expect.isNull(re.matchAsPrefix("foobar", 0));
+  Expect.isNotNull(re.matchAsPrefix("foobar", 3));
+}