[x86 testing] NFC: Create exhaustive vector popcnt ULT/UGT tests
There are bunch of optimization opportunities right now in the vector
popcnt code gen when doing simple less-than/greater-than comparisons, so
let's examine them all to ensure that things don't regress as different
scenarios are fixed. We can always delete some later once some fixes are
Please note: the new files were auto-generated. If people want, I can
commit the short C code that printed out the various combinations.