[patch] Fix problems with -fdebug-types-section

[Cary Coutant]

> I don't believe that it's necessary to copy the children of the class
> declaration at all, and this patch simply removes the code that copies
> those children. If there's a reference in the type unit to one of the
> children of that class, that one child will get copied in as needed.
>
> Bootstraps and passes regression tests. Also tested with a large
> internal test case that previously resulted in out-of-memory during
> compilation.

Sorry, but GDB testing exposed a problem with this patch. It turns out
that it IS necessary to copy children of a non-declaration DIE, such
as DW_TAG_array_type, so my patch was a little too aggressive in
completely removing that loop. I'll have a replacement patch on the
way after a bit more GDB testing.

-cary