message: Fix no_cross_doctests race condition.
diff: @@ -594,10 +594,11 @@ fn no_cross_doctests() {
  let target = rustc_host();
  p.cargo("test -v --target")
  .arg(&target)
  - .with_stderr(&format!(
  + // Unordered since the two `rustc` invocations happen concurrently.
  + .with_stderr_unordered(&format!(
  "\
  [COMPILING] foo v0.0.1 ([CWD])
  -[RUNNING] `rustc --crate-name foo [..]
  +[RUNNING] `rustc --crate-name foo [..]--crate-type lib[..]
  [RUNNING] `rustc --crate-name foo [..]--test[..]
  [FINISHED] test [unoptimized + debuginfo] target(s) in [..]
  [RUNNING] `[CWD]/target/{target}/debug/deps/foo-[..][EXE]`
  