[Matrix] Create inbounds GEPs for matrix load/stores. (#197710)
LowerMatrixIntrinsics creates multiple loads/stores + GEPs for larger
matrix load/stores. Those GEPs compute offsets into the memory accessed
by the larger loads/stores, so those GEPs must be inbounds, otherwise
the larger load would access memory out-of-bounds.
PR: https://github.com/llvm/llvm-project/pull/197710