[InstCombine] Test cases for D154937

Create test cases for the following two folds:

(icmp eq X, C) | (icmp ult Other, (X - C)) -> (icmp ule Other, (X - (C + 1)))
(icmp ne X, C) & (icmp uge Other, (X - C)) -> (icmp ugt Other, (X - (C + 1)))

Differential Revision: https://reviews.llvm.org/D154938