Rollup merge of #153709 - zetanumbers:from_cycle_error_cleanup, r=nnethercote

Fix hypothetical ICE in `variances_of`

A cleanup based on rust-lang/rust#153694.

~~This PR changes panic messages in `fn_sig`'s `value_from_cycle_error` to more fitting ones.~~ Also this PR makes `variances_of`'s `value_from_cycle_error` to utilize new query key argument instead of extracting it from `CycleError`.

Closes rust-lang/rust#127971

r? @nnethercote

Author: JonathanBrouwer