Auto merge of #64543 - pietroalbini:revert-miri-manifest, r=pietroalbini

Revert #64451

#64451 is making the release process panic, causing today's missing nightly (see https://github.com/rust-lang/rust/issues/64540). This reverts that PR, but I'm happy to review a fixed version of it.

cc @RalfJung
r? @ghost

Fixes https://github.com/rust-lang/rust/issues/64540