Rollup of 8 pull requests
Successful merges:
- #115548 (Extract parallel operations in `rustc_data_structures::sync` into a new `parallel` submodule)
- #115591 (Add regression test for LLVM 17-rc3 miscompile)
- #115631 (Don't ICE when computing ctype's `repr_nullable_ptr` for possibly-unsized ty)
- #115708 (fix homogeneous_aggregate not ignoring some ZST)
- #115730 (Some more small driver refactors)
- #115749 (Allow loading the SMIR for constants and statics)
- #115757 (Add a test for #108030)
- #115761 (Update books)
r? `@ghost`
`@rustbot` modify labels: rollup
b4e54c6e39