goose: add test that disambiguate contains the base name
goose: add test that disambiguate contains the base name

No behavior change, just more unit testing.

Reviewed-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Chris Lewis <8e2d25107d002898669bf69d794c874265914ba2@google.com>

google/wire,google/wire