[GPU] Use affine.delinearize_index for MMA tiles and vector distribution

[krzysz00]

This commit updates some by-hand delinearizations in MMA tile generation and vector distribution to use affine.delinearize_index instead.

The main tricky thing here is that a lot of that MMA code would use (id / stride) % size, whereas delinearize's outputs all have the form (id % stride) / nextStride. In all the cases at issue, we could use a utility to convert arrays of sizes and strides to a permutation on a delinearization basis.

In order to not break existing tests, the trivial-loop detector had to be manually instrumented to support delinearize_index (and I got util.assume.int while I was there). (I suspect there're a few other cases, and that, long-term, that detector should be using one of the bounds interfaces, but that's not this PR)

[krzysz00]

Update: staring at tests showed that I should go implement the value bounds op interfaces on the affine.delinearize_index and affine.linearize_index because there were some single-iteration loops that weren't getting eliminated.