Misc. updates/fixes to analysis utils used for DMA generation; update DMA

generation pass to make it drop certain assumptions, complete TODOs.

- multiple fixes for getMemoryFootprintBytes
  - pass loopDepth correctly from getMemoryFootprintBytes()
  - use union while computing memory footprints

- bug fixes for addAffineForOpDomain
  - take into account loop step
  - add domains of other loop IVs in turn that might have been used in the bounds

- dma-generate: drop assumption of "non-unit stride loops being tile space loops
  and skipping those and recursing to inner depths"; DMA generation is now purely
  based on available fast mem capacity and memory footprint's calculated

- handle memory region compute failures/bailouts correctly from dma-generate

- loop tiling cleanup/NFC

- update some debug and error messages to use emitNote/emitError in
  pipeline-data-transfer pass - NFC

PiperOrigin-RevId: 234245969