[X86] Limit the scope of the min/max canonicalization in combineSelect

Previously the transform was doing these two canonicalizations
(x > y) ? x : y -> (x >= y) ? x : y
(x < y) ? x : y -> (x <= y) ? x : y

But those don't seem to be useful generally. And they actively
pessimize the cases in PR47049.

This patch limits it to
(x > 0) ? x : 0 -> (x >= 0) ? x : 0
(x < -1) ? x : -1 -> (x <= -1) ? x : -1

These are the cases mentioned in the comments as the motivation
for the canonicalization. These allow the CMOV to use the S
flag from the compare thus improving opportunities to use a TEST
or the flags from an arithmetic instruction.