Rollup merge of #119668 - cjgillot:transform-promote, r=oli-obk

Simplify implementation of MIR promotion

Non-functional changes.
Best read ignoring whitespace.

Author: GuillaumeGomez

compiler/rustc_const_eval/src/transform/mod.rs

@@ -1,3 +1,2 @@
 pub mod check_consts;
-pub mod promote_consts;
 pub mod validate;

compiler/rustc_mir_transform/src/lib.rs

@@ -1,5 +1,6 @@
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
+#![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(cow_is_borrowed)]
 #![feature(decl_macro)]
@@ -94,6 +95,7 @@ mod multiple_return_terminators;
 mod normalize_array_len;
 mod nrvo;
 mod prettify;
+mod promote_consts;
 mod ref_prop;
 mod remove_noop_landing_pads;
 mod remove_storage_markers;
@@ -115,7 +117,6 @@ mod uninhabited_enum_branching;
 mod unreachable_prop;
 
 use rustc_const_eval::transform::check_consts::{self, ConstCx};
-use rustc_const_eval::transform::promote_consts;
 use rustc_const_eval::transform::validate;
 use rustc_mir_dataflow::rustc_peek;