Accept time zones like GMT-8 in the legacy date parser

test/mjsunit/regress/regress-crbug-422858.js

Index: test/mjsunit/regress/regress-crbug-422858.js
diff --git a/test/mjsunit/regress/regress-crbug-422858.js b/test/mjsunit/regress/regress-crbug-422858.js
new file mode 100644
index 0000000000000000000000000000000000000000..e2227e2c6282e1343d7183887b6ccfe6ed67182b
--- /dev/null
+++ b/test/mjsunit/regress/regress-crbug-422858.js
@@ -0,0 +1,18 @@
+// Copyright 2015 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.
+
+var date = new Date("2016/01/02 10:00 GMT-8")
+assertEquals(0, date.getMinutes());

[jungshik at Google, 2016/01/04 20:05:08]

Would it be a good idea to check hours as well ? 

[Dan Ehrenberg, 2016/01/04 23:03:53]

Good point; done

+
+date = new Date("2016/01/02 10:00 GMT-12")
+assertEquals(0, date.getMinutes());
+
+date = new Date("2016/01/02 10:00 GMT-123")
+assertEquals(23, date.getMinutes());
+
+date = new Date("2016/01/02 10:00 GMT-0856")
+assertEquals(56, date.getMinutes());
+
+date = new Date("2016/01/02 10:00 GMT-08000")
+assertEquals(NaN, date.getMinutes());