[CVP] Simplify SRem when constantrange abs(lhs) < abs(rhs)

For `srem x, y`, if abs(constant range of x) less than abs(constant
range of y), we can simplify it as:
`srem x, y => x` if y is guaranteed to be positive.
'srem x, y => -x' if y is guaranteed to be negative.

Differential Revision: https://reviews.llvm.org/D140405