Issue 9273 & 9284 - DMD segfaults with templated ctors

[Issue 9273](http://d.puremagic.com/issues/show_bug.cgi?id=9273) - DMD segfaults with templated ctors in implicit super call
[Issue 9284](http://d.puremagic.com/issues/show_bug.cgi?id=9284) - DMD segfaults with templated ctors in constructor delegation