[llvm] [WIP] Extend data layout to add non zero null value for address space. (PR #83109)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

This patch needs more of the functionality changes to be meaningfully reviewed; this is pretty minimal for the datalayout parts, so perhaps it would be best to open a new PR for the next pieces 

https://github.com/llvm/llvm-project/pull/83109