Fix issue for nested record types with -fdump-ada-spec

Fix issue for nested record types with -fdump-ada-spec

Ada does not support anonymous record declarations nested in other record
declarations so -fdump-ada-spec needs to unnest them, and this contains a
few fixes for this machinery.

gcc/c-family/
	* c-ada-spec.c (dump_ada_macros): Minor tweaks.
	(dump_ada_decl_name): Likewise.
	(dump_anonymous_type_name): Remove parent parameter and adjust.
	(dump_sloc): Minor tweak.
	(dump_ada_array_type): Remove type parameter and adjust.
	(dump_ada_enum_type): Remove parent parameter and adjust.
	(dump_ada_node): Adjust calls to above functions.
	(dumped_anonymous_types): New global variable.
	(dump_nested_types_1): Rename into...
	(dump_nested_types): ...this.
	(dump_nested_type): Remove parent and dumped_types parameters.
	<ARRAY_TYPE>: Replace dumped_types with dumped_anonymous_types.
	Adjust calls to dump_anonymous_type_name and dump_ada_array_type.
	(dump_ada_specs): Initialize and free dumped_anonymous_types.