Remove cplus_specific from general_symbol_info.

Remove cplus_specific from general_symbol_info.

This patch reverts the addition of cplus_specific added here:

2010-07-16  Sami Wagiaalla  <swagiaal@redhat.com>

	* symtab.h (symbol_set_demangled_name): Now takes an optional objfile*
	argument.
	(cplus_specific): New struct.
	* symtab.c (symbol_set_demangled_name): Updated.
	Use cplus_specific for cplus symbols.
	(symbol_get_demangled_name): Retrive the name from the cplus_specific
	struct for cplus symbols.
	(symbol_init_language_specific): Set cplus_specific for cplus symbols.
	(symbol_set_names): Pass objfile to symbol_set_demangled_name.
	* symtab.c (symbol_init_cplus_specific): New function.

It was added in anticipation of improved template support:

https://sourceware.org/ml/gdb-patches/2010-05/msg00594.html
https://sourceware.org/ml/gdb-patches/2010-07/msg00284.html

However, minsyms pay the price for this space too.
For my standard benchmark this patch gets back 44MB of memory
when gdb starts.  [There's still ~440MB of memory used
by the demangled ELF symbols of this benchmark, but that's another topic.]

When the improved templated support is added,
I wonder if this can be moved to struct symbol.
Hmmm, we already have a special version of
struct symbol for templates (struct template_symbol).

gdb/ChangeLog:

	* symtab.c (symbol_init_cplus_specific): Delete.
	(symbol_set_demangled_name): Remove special c++ support.
	(symbol_get_demangled_name, symbol_set_language): Ditto.
	* symtab.h (struct cplus_specific): Delete.
	(struct general_symbol_info) <language_specific>: Remove
	cplus_specific.