Revert "[SLP]Improve minbitwidth analysis for abs/smin/smax/umin/umax intrinsics."

This reverts commit 66b52807.

This commit caused miscompilations, breaking tests in the libyuv
testsuite - see
https://github.com/llvm/llvm-project/pull/86135#issuecomment-2041049709
for more details.