Rollup merge of #131200 - ismailarilik:handle-potential-query-instability-lint-for-rustc-query_system, r=fee1-dead

Handle `rustc_query_system` cases of `rustc::potential_query_instability` lint

This PR removes `#![allow(rustc::potential_query_instability)]` line from [`compiler/rustc_query_system/src/lib.rs`](https://github.com/rust-lang/rust/blob/master/compiler/rustc_query_system/src/lib.rs#L2) and converts `FxHash{Map,Set}` types into `FxIndex{Map,Set}` to suppress lint errors.

A somewhat tracking issue: rust-lang/rust#84447

r? `@compiler-errors`

Author: matthiaskrgr