Fix dart2js replace to escape all dollar characters in the replacement string.

tests/corelib/string_replace_dollar_test.dart

Index: tests/corelib/string_replace_dollar_test.dart
diff --git a/tests/corelib/string_replace_dollar_test.dart b/tests/corelib/string_replace_dollar_test.dart
index 6a684f0be392f1bcb361384b54698c1368611fd3..c0077a05965d7e1ede883b8db9f830eb8ebdfa24 100644
--- a/tests/corelib/string_replace_dollar_test.dart
+++ b/tests/corelib/string_replace_dollar_test.dart
@@ -16,4 +16,12 @@ main() {
   Expect.equals(jsText, htmlOut);
   htmlOut = htmlStr.replaceFirst(new RegExp("%%DART"), jsText);
   Expect.equals(jsText, htmlOut);
+
+  // Regression test, http://dartbug.com/17886
+  String doubleDollar = r"$'$`";
+  var string = r"flip-flip-flop";
+  var result = string.replaceFirst("flip", doubleDollar);
+  Expect.equals(r"$'$`-flip-flop", result);
+  result = string.replaceAll("flip", doubleDollar);
+  Expect.equals(r"$'$`-$'$`-flop", result);
 }