Remove MULTI_OBJFILE_P

Remove MULTI_OBJFILE_P

This removes the MULTI_OBJFILE_P macro in favor of a method on the
program space.

gdb/ChangeLog
2019-12-12  Tom Tromey  <tom@tromey.com>

	* progspace.c (program_space::multi_objfile_p): New method.
	* printcmd.c (info_symbol_command): Update.
	* maint.c (maintenance_translate_address): Update.
	* objfiles.h (MULTI_OBJFILE_P): Remove.
	* progspace.h (struct program_space) <multi_objfile_p>: New
	method.

Change-Id: I2779e26ea8909078d63fea8f13bce94cab73948c