[X86] Attempt to fold EFLAGS into X86ISD::ADD/SUB ops

We already use combineAddOrSubToADCOrSBB to fold extended EFLAGS results into ISD::ADD/SUB ops as X86ISD::ADC/SBB carry ops.

This patch extends this to also try to fold EFLAGS results with X86ISD::ADD/SUB ops

Differential Revision: https://reviews.llvm.org/D125642