[ARM] KnownBits for CSINC/CSNEG/CSINV

This adds some simple known bits handling for the three CSINC/NEG/INV
instructions. From the operands known bits we can compute the common
bits of the first operand and incremented/negated/inverted second
operand. The first, especially CSINC ZR, ZR, comes up fair amount in the
tests. The others are more rare so a unit test for them is added.

Differential Revision: https://reviews.llvm.org/D97788