* Make all of the refineAbstractType functions work identically

* Remove ambiguous code that caused problems with understanding how stuff
  worked.
* Implement DerivedType::typeIsRefined right.  Add a big comment talking
  about it.
* The removeUserFromConcrete method already checks to see if the type is
  not abstract, so no need to duplicate the test all over this code

This checkin makes all of the type parsing related failures work.  All
Assembler Regression tests now pass!

llvm-svn: 2127