[google/gcc-4_7, trunk] Fix problem with -fdebug-types-section and template instantiations

[Sterling Augustine]

> Google ref b/7041390.
>
>
> 2012-08-25   Cary Coutant  <ccoutant@google.com>
>
> gcc/
> 	* dwarf2out.c (is_template_instantiation): New function.
> 	(should_move_die_to_comdat): Reject types that are template
> 	instantiations.

This patch is OK for google 4.7

Sterling