fixes#24492
Kind of a goofy way of doing this, but we count how many derefs were
used for the first parameter before calling `builtinFieldAccess`, then
count after, and if there are more now than before, we remove the added
derefs. I thought maybe getting rid of #18298 would simplify it but
maybe this would still be the best way.
For better encapsulation we could make `dotTransformation` take an
`nOrig` param instead but this would be less efficient since it would
need a copy, though `semAsgn` already makes one.
2529f33760