[AMDGPU] Re-enabling divergence predicates for min/max

This patch enables divergence predicates for min/max nodes.
It makes ISD::MIN/MAX selected to S_MIN_I(U)32/S_MAX_I(U)32 or V_MIN_I(U)32_e64/V_MAX_I(U)32_e64

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D115954