…-Simulacrum

Reinstate preloading of some dll imports

I've now come around to the conclusion that there is a justification for pre-loading the synchronization functions `WaitOnAddress` and `WakeByAddressSingle`. I've found this to have a particularly impact in testing frameworks that may have short lived processes which immediately spawn lots of threads.

Also, because pre-main initializers imply a single-threaded environment, we can switch back to using relaxed atomics which might be a minor perf improvement on some platforms (though I doubt it's particularly notable).

r? `@Mark-Simulacrum` and sorry for the churn here.

For convenience I'll summarise previous issues with preloading and the solutions that are included in this PR (if any):

**Issue:** User pre-main initializers may be run before std's
**Solution:** The std now uses initializers that are guaranteed to run earlier than the old initializers. A note is also added that users should not copy std's behaviour if they want to ensure they run their initializers after std.

**Issue:** Miri does not understand pre-main initializers.
**Solution:** For miri only, run the function loading lazily instead.

**Issue:** We should ideally use `LoadLibrary` to get "api-ms-win-core-synch-l1-2-0". Only "ntdll" and "kernel32" are guaranteed to always be loaded.
**Solution:** None. We can't use `LoadLibrary` pre-main. However, in the past `GetModuleHandle` has always worked in practice so this should hopefully not be a problem.

If/when Windows 7 support is dropped, we can finally remove all this for good and just use normal imports.

…iaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#100970 (Allow deriving multipart suggestions)
 - rust-lang#100984 (Reinstate preloading of some dll imports)
 - rust-lang#101011 (Use getentropy when possible on all Apple platforms)
 - rust-lang#101025 (Add tier-3 support for powerpc64 and riscv64 openbsd)
 - rust-lang#101049 (Remove span fatal from ast lowering)
 - rust-lang#101100 (Make call suggestions more general and more accurate)
 - rust-lang#101171 (Fix UB from misalignment and provenance widening in `std::sys::windows`)
 - rust-lang#101185 (Tweak `WellFormedLoc`s a bit)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup