[mlir][sparse] enable integral abs recognition

The end-to-end test for this new feature also exposed a bug
in LLVM IR lowering (since then, fixed), where we need to account
for the min-poison bit as extra argument.

    declare i32 @llvm.abs.i32(i32 <src>, i1 <is_int_min_poison>)

Reviewed By: bixia

Differential Revision: https://reviews.llvm.org/D131712