gdb: Delete SYMBOL_OBJ_SECTION and MSYMBOL_OBJ_SECTION

gdb: Delete SYMBOL_OBJ_SECTION and MSYMBOL_OBJ_SECTION

Replace the two macros SYMBOL_OBJ_SECTION and MSYMBOL_OBJ_SECTION with
a member function on general_symbol_info.

There should be no user visible change after this commit.

gdb/ChangeLog:

	* breakpoint.c (resolve_sal_pc): Replace SYMBOL_OBJ_SECTION and
	MSYMBOL_OBJ_SECTION.
	* findvar.c (language_defn::read_var_value): Likewise.
	* infcmd.c (jump_command): Likewise.
	* linespec.c (minsym_found): Likewise.
	* maint.c (maintenance_translate_address): Likewise.
	* minsyms.c (lookup_minimal_symbol_by_pc_section): Likewise.
	(minimal_symbol_upper_bound): Likewise.
	* parse.c (find_minsym_type_and_address): Likewise.
	(operator_check_standard): Likewise.
	* printcmd.c (info_address_command): Likewise.
	* symmisc.c (dump_msymbols): Likewise.
	(print_symbol): Likewise.
	* symtab.c (general_symbol_info::obj_section): Define new
	function.
	(fixup_symbol_section): Replace SYMBOL_OBJ_SECTION.
	(find_pc_sect_compunit_symtab): Likewise.
	(find_function_start_sal): Likewise.
	(skip_prologue_sal): Replace SYMBOL_OBJ_SECTION and
	MSYMBOL_OBJ_SECTION.
	* symtab.h (struct general_symbol_info) <obj_section>: Declare new
	function.
	(SYMBOL_OBJ_SECTION): Delete.
	(MSYMBOL_OBJ_SECTION): Delete.