Add test for regexp issue from 936

It seems that somewhere, the ungreedy flag doesn't work correctly.

exec/tests/regex/ungreedy.js

+var x = '/opt/sbbs/fido/outbound.00a/00010001.flo';
+if (x.replace(/\.[^\.]*?$/, '.bsy') === x) {
+	throw new Error("Ungreedy match failed!");
+}