Move tests to their proper place
Move tests to their proper place

Moves tests for #ref and #unref to their logical place under
TestFundamentalObject, even though we need TestFundamentalSubObject to
actually test them. This eliminates two skips.

mvz/gir_ffi,jcupitt/gir_ffi,jcupitt/gir_ffi,mvz/gir_ffi,mvz/gir_ffi