Fix gdb.lookup_type for function-local types

Fix gdb.lookup_type for function-local types

Looking for a type defined locally in a function doesn't work
any more since the introduction of TYPE_DOMAIN:
```
(gdb) python print (gdb.lookup_type ('main()::Local'))
Python Exception <class 'gdb.error'>: No type named main()::Local.
Error occurred in Python: No type named main()::Local.
```

cp_search_static_and_baseclasses was simply missing a check for
SEARCH_TYPE_DOMAIN, now it works again:
```
(gdb) python print (gdb.lookup_type ('main()::Local'))
Local
```

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31922
Approved-By: Tom Tromey <tom@tromey.com>