Auto merge of #51857 - pietroalbini:beta-backports, r=pietroalbini
[beta] Rollup backports
Merged and approved:
* #51725: Do not build LLVM tools for any of the tools
* #51852: Don't use `ParamEnv::reveal_all()` if there is a real one available
* #51686: yet another "old borrowck" bug around match default bindings
* #51868: Remove process::id from 'Stabilized APIs' in 1.27.0 release notes
* #51335: Prohibit `global_allocator` in submodules
r? @ghost