Convert ada-lang.c to type-safe registry API

Convert ada-lang.c to type-safe registry API

This changes ada-lang.c to use the type-safe registry API.

gdb/ChangeLog
2019-05-08  Tom Tromey  <tom@tromey.com>

	* ada-lang.c (struct ada_inferior_data): Add initializers.
	(ada_inferior_data): Change type.
	(ada_inferior_data_cleanup): Remove.
	(get_ada_inferior_data, ada_inferior_exit)
	(struct ada_pspace_data): Add initializers, destructor.
	(ada_pspace_data_handle): Change type.
	(get_ada_pspace_data): Update.
	(ada_pspace_data_cleanup): Remove.