[AMDGPU] Fix liveness in the SIOptimizeExecMaskingPreRA.cpp

If a condition register def happens past the newly created use
we do not properly update LIS. It has two problems:

1) We do not extend defining segment to the end of its block
   marking it a live-out (this is regression after
   https://reviews.llvm.org/rG09d38dd7704a52e8ad2d5f8f39aaeccf107f4c56)

2) We do not extend use segment to the beginning of the use block
   marking it a live-in.

Fixes: SWDEV-379563

Differential Revision: https://reviews.llvm.org/D143302