[regexp] quantifier refers to the surrogate pair in unicode regexp.

test/mjsunit/harmony/unicode-escapes-in-regexps.js

Index: test/mjsunit/harmony/unicode-escapes-in-regexps.js
diff --git a/test/mjsunit/harmony/unicode-escapes-in-regexps.js b/test/mjsunit/harmony/unicode-escapes-in-regexps.js
index a4c5c5f0f245d46eb8e2303fa5096b884a64c5e5..f591dac930194037ac2f498bddc33c4f2a5ca92c 100644
--- a/test/mjsunit/harmony/unicode-escapes-in-regexps.js
+++ b/test/mjsunit/harmony/unicode-escapes-in-regexps.js
@@ -247,3 +247,11 @@ assertTrue(/(\u{12345}|\u{23456}).\1/u.test("\u{12345}b\u{12345}"));
 assertFalse(new RegExp("(\u{12345}|\u{23456}).\\1", "u").test(
     "\u{12345}b\u{23456}"));
 assertFalse(/(\u{12345}|\u{23456}).\1/u.test("\u{12345}b\u{23456}"));
+
+// Quantifier.
+assertTrue(new RegExp("\u{12345}{3}", "u").test("\u{12345}\u{12345}\u{12345}"));
+assertTrue(/\u{12345}{3}/u.test("\u{12345}\u{12345}\u{12345}"));
+assertTrue(new RegExp("\u{12345}{3}").test("\u{12345}\udf45\udf45"));
+assertTrue(/\ud808\udf45{3}/u.test("\u{12345}\udf45\udf45"));
+assertFalse(new RegExp("\u{12345}{3}", "u").test("\u{12345}\udf45\udf45"));
+assertFalse(/\u{12345}{3}/u.test("\u{12345}\udf45\udf45"));