Fix error in expression evalutation in linker output maps.
    
    	PR 24008
    	* ldexp.h (lang_phase_type): Add lang_fixed_phase_enum.
    	* ldexp.c (fold_name): Move expld.assign_name check later to
    	avoid an extra lookup.
    	(exp_fold_tree_1): When lang_fixed_phase_enum, don't change symbol
    	values, and don't clear expld.assign_name.
    	* ldlang.c (lang_map): Set expld.phase to lang_fixed_phase_enum.
    	(print_assignment): Resolve entire assignment expression.
    	Don't access symbol u.def unless symbol is defined.