Add pretty-printing for class template specializations, e.g.,

  'struct A<double, int>'

In the "template instantiation depth exceeded" message, print
"-ftemplate-depth-N" rather than "-ftemplate-depth=N".

An unnamed tag type that is declared with a typedef, e.g., 

  typedef struct { int x, y; } Point;

can be used as a template argument. Allow this, and check that we get
sensible pretty-printing for such things.

llvm-svn: 66560