[InstSimplify] fold redundant select of min/max, part 2

This extends e5d15e11 to handle the inverse predicates
(there's probably a more elegant way to specify the preds).

These patterns correspond to the existing simplify:
max (min X, Y), X --> X
...and extra preds for (non)equality.

The tests cycle through all 10 icmp preds for each min/max
variant with 4 swapped operand patterns each (and the min/max
operands are commuted in every other test within those).

Some Alive2 examples to verify:
https://alive2.llvm.org/ce/z/XMvEKQ
https://alive2.llvm.org/ce/z/QpMChr