Minor optimization of static ggc roots.

Minor optimization of static ggc roots.

	* jcf-parse.c (parse_roots):  New static field.
	(current_field, current_method, current_file_list):  Replace by macros
	naming fields of parse_roots.
	(init_jcf_parse):  Combine 3 ggc_add_tree_root calls to 1.
	* class.c (class_roots):  New static field.
	(registered_class, fields_ident, info_ident, class_list):
	New macros naming fields of parse_roots.
	(build_static_field_ref):  Don't register roots here.
	(layout_class):  Static field list replaced by macro class_list.
	(init_class_processing):  Call ggc_add_tree_root for 4 roots.
	Initialize fields_ident and info_ident here.

From-SVN: r39174