Recommit "[TypePromotion] Support positive addition amounts in isSafeWrap. (#81690)"

With special case with Add constant is 0.

Original message:
We can support these by changing the sext promotion to -zext(-C) and
replacing a sgt check with ugt. Reframing the logic in terms of how the
unsigned range are affected. More comments in the patch.

The new cases check isLegalAddImmediate to avoid some
regressions in lit tests.