In dependent-capture, previously we'd see that %tmp4 is captured due to
the first store. We'd cache this info in CapturedBeforeReturn and
InvisibleToCallerAfterRet. Then the first store is then removed, causing
the cached values to be wrong.
We also need to revisit everything because normally we work backwards
when removing stores at the end of the function, but in this case
removing an earlier store causes a later store to be removable.