Auto merge of #119627 - oli-obk:const_prop_lint_n̵o̵n̵sense, r=cjgillot

Remove all ConstPropNonsense

We track all locals and projections on them ourselves within the const propagator and only use the InterpCx to actually do some low level operations or read from constants (via `OpTy` we get for said constants).

This helps moving the const prop lint out from the normal pipeline and running it just based on borrowck information. This in turn allows us to make progress on rust-lang/rust#108730 (comment)

there are various follow up cleanups that can be done after this PR (e.g. not matching on Rvalue twice and doing binop checks twice), but lets try landing this one first.

r? `@RalfJung`