Make demangled_name_entry::language not a bitfield

Make demangled_name_entry::language not a bitfield

Having it as a bitfield causes extra work, and this is not memory-sensitive.
Furthermore, once https://sourceware.org/ml/gdb-patches/2019-10/msg00812.html
lands, the bitfield won't even save any memory at all.

gdb/ChangeLog:

2019-10-22  Christian Biesinger  <cbiesinger@google.com>

	* symtab.c (struct demangled_name_entry) <language>: Change from
	bitfield to regular variable.

Change-Id: I4ea31d1cfcbe0f09a09bd058cd304862308dc388