remove or encapsulate the remaining non-query data in tcx
I wound up removing the existing cache around inhabitedness since it didn't seem to be adding much value. I reworked const rvalue promotion, but not that much (i.e., I did not split the computation into bits, as @eddyb had tossed out as a suggestion). But it's now demand driven, at least.
cc @michaelwoerister -- see the `forbid_reads` change in last commit
r? @eddyb -- since the trickiest of this PR is the work on const rvalue promotion
cc #44137
This commit enables configuring the RLS/rustfmt tools to the "broken" state and
actually get it past CI. The main changes here were to update all dist-related
code to handle the situation where the RLS isn't available. This in turn
involved a homegrown preprocessor-like-function to edit the configuration files
we pass to the various combined installer tools.
Oliver Schneider