[PATCH 2/2] Remove dwarf2_cu::language

[Tom Tromey]

Tom> I didn't give it much thought TBH - I was using dwarf2_per_cu_data::lang
Tom> in my series, and I assumed that this was there for some other important
Tom> reason.  However, I see that this member was added in commit 589902954d
Tom> ("[gdb] Skip imports of c++ CUs"), and from what I can tell, it should
Tom> be fine to switch that code to using dwarf2_cu::language instead.

I went back and looked at all the uses in my new code, and I think
preserving this on the dwarf2_per_cu_data is important.  The new code
works by indexing the DIEs, in a way that's similar to how .debug_names
is supposed to work.  Some code may need the language of an entry for
some kind of processing, but at times where the dwarf2_cu no longer
exists.

Tom