Make sure all types in gdb.ada/homonym testcase are used...

Make sure all types in gdb.ada/homonym testcase are used...

Otherwise, the compiler does not generate any debug info for them.
This fixes 3 FAILs:

    FAIL: gdb.ada/homonym.exp: ptype local_type_subtype at BREAK_1
    FAIL: gdb.ada/homonym.exp: ptype int_type at BREAK_1
    FAIL: gdb.ada/homonym.exp: ptype local_type_subtype at BREAK_2

gdb/testsuite/ChangeLog:

        * gdb.ada/homonym/pck.ads, gdb.ada/homonym/pck.adb: New files.
        * gdb.ada/homonym/homonym.adb: For use of all types defined
        locally inside both Get_Value subprograms.