Auto merge of #142540 - cjgillot:renumber-cfg, r=fee1-dead

Pre-compute MIR CFG caches for borrowck and other analyses

I was puzzled that rust-lang/rust#142390 introduces additional computations of CFG traversals: borrowck computes them, right?

It turns out that borrowck clones the MIR body, so doesn't share its cache with other analyses.

This PR:
- forces the computation of all caches in `mir_promoted` query;
- modifies region renumbering to avoid dropping that cache.

Author: bors