Move types_deeply_equal from py-type.c to gdbtypes.c.

Move types_deeply_equal from py-type.c to gdbtypes.c.

	* gdbtypes.c: #include bcache.h, dwarf2loc.h.
	(type_equality_entry): Move here from python/py-type.c.
	(type_equality_entry_d): Ditto.
	(compare_maybe_null_strings, check_types_equal): Ditto.
	(check_types_worklist, types_deeply_equal): Ditto.
	* gdbtypes.h (types_deeply_equal): Declare.
	* python/py-type.c: Remove inclusion of bcache.h, dwarf2loc.h.
	(typy_richcompare): Update.