Rollup merge of #138661 - RalfJung:revert-rustc-dev-breakage, r=petrochenkov

Revert: Add *_value methods to proc_macro lib

This reverts rust-lang/rust#136355. That PR caused unexpected breakage:
- the rustc-dev component can no longer be loaded by cargo, which impacts Miri and clippy and likely others
- rustc_lexer can no longer be published to crates.io, which impacts RA

See rust-lang/rust#138647 for context.
Cc `@GuillaumeGomez` `@Amanieu`

Author: matthiaskrgr