fixes#23568, fixes#23310
In #23091 `semFinishOperands` was changed to not be called for `mArrGet`
and `mArrPut`, presumably in preparation for #23188 (not sure why it was
needed in #23091, maybe they got mixed together), since the compiler
handles these later and needs the first argument to not be completely
"typed" since brackets can serve as explicit generic instantiations in
which case the first argument would have to be an unresolved generic
proc (not accepted by `finishOperand`).
In this PR we just make it so `mArrGet` and `mArrPut` specifically skip
calling `finishOperand` on the first argument. This way the generic
arguments in the explicit instantiation get typed, but not the
unresolved generic proc.
