[llvm] [AMDGCN][SIWholeQuadMode] Handle case when SI_KILL_I1_TERMINATOR -1,0 is not the only terminator (PR #122922)

[Juan Manuel Martinez Caamaño via llvm-commits]

https://github.com/jmmartinez commented:

I reworked lowerKillI1/lowerKillF32/splitBlocks to fix the issue and generate less redundant instructions (useless s_branch).

https://github.com/llvm/llvm-project/pull/122922