Auto merge of #69636 - RalfJung:miri, r=nikomatsakis

update miri

Let's make that toolstate green again. :D

This bumps serde in the lockfile, so r? @oli-obk

Fixes https://github.com/rust-lang/rust/issues/69462

Cargo.lock

@@ -2137,6 +2137,7 @@ dependencies = [
  "rustc-workspace-hack",
  "rustc_version",
  "serde",
+ "serde_json",
  "shell-escape",
  "vergen",
 ]

src/bootstrap/test.rs

@@ -391,7 +391,7 @@ fn run(self, builder: &Builder<'_>) {
             // Overwrite bootstrap's `rustc` wrapper overwriting our flags.
             cargo.env("RUSTC_DEBUG_ASSERTIONS", "true");
             // Let cargo-miri know where xargo ended up.
-            cargo.env("XARGO", builder.out.join("bin").join("xargo"));
+            cargo.env("XARGO_CHECK", builder.out.join("bin").join("xargo-check"));
 
             let mut cargo = Command::from(cargo);
             if !try_run(builder, &mut cargo) {