Rollup merge of #137100 - fmease:hirtylow-rm-clauses-wrapper, r=compiler-errors

HIR analysis: Remove unnecessary abstraction over list of clauses

`rustc_hir_analysis::bounds::Bounds` with its methods is nowadays a paper-thin wrapper around `Vec<(Clause, Span)>`s and `Vec::push` essentially.

Its existence slightly annoyed me (and I keep opening its corresp. file instead of the identically named `bounds.rs` in `hir_ty_lowering/` that I actually want most of the time :P).

Opening to check if you agree with inlining it.
r? compiler-errors or reassign

Author: matthiaskrgr