Labelled continue/break can fail in some cases

[Oliver Hunt]

JSC does not handle a continue or break to a label when there are multiple labels at that scope, eg.
	a: 
	b:
	for (var foo = 1; foo < 10; foo++) {
	   if (foo == 4)
		   continue a;
	   print("foo: "+foo);
	}
execution ends up terminating at foo: 3, rather than continuing to to foo: 9

[Oliver Hunt]

Created attachment 19009 [details]
Testcase

Uses setTimeout to trigger the script running as otherwise firefox does not run it for some reason

[Mark Rowe (bdash)]

<rdar://problem/5733160>

[Darin Adler]

Committed revision 30103.