Unrolled build for rust-lang#128612

Rollup merge of rust-lang#128612 - compiler-errors:validate-mir-opt-mir, r=davidtwco

Make `validate_mir` ensure the final MIR for all bodies

A lot of the crashes tests use `-Zpolymorphize` or `-Zdump-mir` for their side effect of computing the `optimized_mir` for all bodies, which will uncover bugs with late MIR passes like the inliner. I don't like having all these tests depend on `-Zpolymorphize` (or other hacky ways) for no reason, so this PR extends the `-Zvalidate-mir` flag to ensure `optimized_mir`/`mir_for_ctfe` for all body owners during the analysis phase.

Two thoughts:
1. This could be moved later in the compilation pipeline I guess? I don't really think it matters, though.
1. This could alternatively be expressed using a new flag, though I don't necessarily see much value in separating these.

For example, rust-lang#128171 could have used this flag, in the `tests/ui/polymorphization/inline-incorrect-early-bound.rs`.

r? mir

compiler/rustc_interface/src/passes.rs

@@ -818,6 +818,13 @@ fn run_required_analyses(tcx: TyCtxt<'_>) {
     });
     sess.time("layout_testing", || layout_test::test_layout(tcx));
     sess.time("abi_testing", || abi_test::test_abi(tcx));
+    if tcx.sess.opts.unstable_opts.validate_mir {
+        sess.time("ensuring_optimized_MIR_is_computable", || {
+            tcx.hir().par_body_owners(|def_id| {
+                tcx.instance_mir(ty::InstanceKind::Item(def_id.into()));
+            });
+        });
+    }
 }
 
 /// Runs the type-checking, region checking and other miscellaneous analysis

tests/crashes/121127.rs

@@ -1,5 +1,5 @@
 //@ known-bug: #121127
-//@ compile-flags: -Zpolymorphize=on -Zinline-mir=yes -C debuginfo=2
+//@ compile-flags: -Zvalidate-mir -Zinline-mir=yes -C debuginfo=2
 // Note that as of PR#123949 this only crashes with debuginfo enabled
 
 #![feature(specialization)]

tests/crashes/122909.rs

@@ -1,4 +1,4 @@
-//@ compile-flags: -Zpolymorphize=on -Zinline-mir=yes
+//@ compile-flags: -Zvalidate-mir -Zinline-mir=yes
 //@ known-bug: #122909
 
 

tests/crashes/126896.rs

@@ -1,5 +1,5 @@
 //@ known-bug: rust-lang/rust#126896
-//@ compile-flags: -Zpolymorphize=on -Zinline-mir=yes
+//@ compile-flags: -Zvalidate-mir -Zinline-mir=yes
 
 #![feature(type_alias_impl_trait)]
 type Two<'a, 'b> = impl std::fmt::Debug;