More cleanup for --enable-mapped-location.

More cleanup for --enable-mapped-location.

	* class.c (push_class):  If USE_MAPPED_LOCATION don't set
	input_location here.  Instead do it in give_name_to_class.
	(build_class_ref):  Set DECL_ARTIFICIAL, for the sake of dwarf2out.
	* expr.c (expand_byte_code): Call linemap_line_start.
	* expr.c (build_expr_wfl):  If USE_MAPPED_LOCATION, change final
	parameters to a source_location.  Don't need EXPR_WFL_FILENAME_NODE.
	(expr_add_location):  New function, if USE_MAPPED_LOCATION.
	* class.c (maybe_layout_super_class):  Adjust build_expr_wfl call
	to USE_MAPPED_LOCATION case.

From-SVN: r88365