message: Update dylib check test to explicitly express that it doesn't cause rebuilds
diff: @@ -301,7 +301,7 @@ fn issue_3419() {
  // Check on a dylib should have a different metadata hash than build.
  #[test]
  -fn check_dylib() {
  +fn dylib_check_preserves_build_cache() {
  let p = project("foo")
  .file("Cargo.toml", r#"
  [package]
  @@ -317,25 +317,21 @@ fn check_dylib() {
  .file("src/lib.rs", "")
  .build();
  - let build_output = t!(String::from_utf8(
  - t!(p.cargo("build").arg("-v").exec_with_output())
  - .stderr,
  - ));
  - let build_metadata = build_output
  - .split_whitespace()
  - .find(|arg| arg.starts_with("metadata="))
  - .unwrap();
  -
  - let check_output = t!(String::from_utf8(
  - t!(p.cargo("check").arg("-v").exec_with_output())
  - .stderr,
  - ));
  - let check_metadata = check_output
  - .split_whitespace()
  - .find(|arg| arg.starts_with("metadata="))
  - .unwrap();
  -
  - assert_ne!(build_metadata, check_metadata);
  + assert_that(p.cargo("build"),
  + execs().with_status(0)
  + .with_stderr("\
  +[..]Compiling foo v0.1.0 ([..])
  +[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
  +"));
  +
  + assert_that(p.cargo("check"),
  + execs().with_status(0));
  +
  + assert_that(p.cargo("build"),
  + execs().with_status(0)
  + .with_stderr("\
  +[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
  +"));
  }
  // test `cargo rustc --profile check`
  