gdb/fortran: Don't include module symbols when searching for types

gdb/fortran: Don't include module symbols when searching for types

Currently the 'info types' command will return symbols that correspond
to Fortran modules.  This is because the symbols are created with
domain MODULE_DOMAIN and address_class LOC_TYPEDEF.  The address_class
LOC_TYPEDEF is the same address_class used for type symbols which is
why the modules show up when listing types.

This commit explicitly prevents symbols in the MODULE_DOMAIN from
appearing when we search for symbols in the TYPES_DOMAIN, this
prevents the Fortran module symbols from appearing in the output of
'info types'.

gdb/ChangeLog:

	* symtab.c (search_symbols): Don't include MODULE_DOMAIN symbols
	when searching for types.

gdb/testsuite/ChangeLog:

	* gdb.fortran/info-types.exp: Add module.
	* gdb.fortran/info-types.f90: Update expected results.