Make `compare_predicate_entailment` no longer a query
Make `compare_predicate_entailment` so it's no longer a query (again), and splits out the new logic (that equates the return types to infer RPITITs) into its own query. This means that this new query (now called `collect_trait_impl_trait_tys`) is no longer executed for non-RPITIT cases.
This should improve perf (https://github.com/rust-lang/rust/pull/101224#issuecomment-1241682203), though in practice we see that these some crates remain from the primary regressions list on the original report... They are all <= 0.43% regression and seemingly only on the incr-full scenario for all of them.
I am at a loss for what might be causing this regression other than what I fixed here, since we don't introduce much new non-RPITIT logic except for some `def_kind` query calls in some places, for example, like projection. Maybe that's it?
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Originally this PR was opened to test enabling `cache_on_disk` (62164aaaa11) but that didn't turn out to be very useful (https://github.com/rust-lang/rust/pull/101615#issuecomment-1242403205), so that led me to just split the query (and rename the PR).
1ce51982b8