[REG2.066a] Issue 11919 - GitHub HEAD regression for getAttributes trait (DMD CORE DUMP)

https://d.puremagic.com/issues/show_bug.cgi?id=11919

There's multiple factors.

1. By fixing [issue 8244](http://d.puremagic.com/issues/show_bug.cgi?id=8244)(#2855), `is(B[])` at line 7 in foobar.d is changed to return true from 2.065.
   Then, `doBar!Bar` will instantiate `doBar!Foo` and `doBar!Object`, unlike 2.064.
2. By fixing [issue 11844](http://d.puremagic.com/issues/show_bug.cgi?id=11844)(#3056), semantic analysis timing for UDAs has been changed, and it had accidentally introduced ICE issue with the OP test case.
3. Even if we fix the ICE in 2, [bug 9741](http://d.puremagic.com/issues/show_bug.cgi?id=9741) will report incorrect 'undefined identifier' error. To fundamentally fix the root issue, I fix the bug in this PR, too.

Therefore, also fixes [Issue 9741](http://d.puremagic.com/issues/show_bug.cgi?id=9741) - undefined identifier with User Defined Attribute