message: testsuite/doc: Check the arguments used to invoke the browser
  Previously we apparently weren't doing this as we weren't checking
  stdout.
diff: @@ -1184,6 +1184,7 @@ fn doc_workspace_open_different_library_and_package_names() {
  .env("BROWSER", "echo")
  .with_stderr_contains("[..] Documenting foo v0.1.0 ([..])")
  .with_stderr_contains("[..] [CWD]/target/doc/foolib/index.html")
  + .with_stdout_contains("[CWD]/target/doc/foolib/index.html")
  .run();
  p.change_file(
  @@ -1197,7 +1198,7 @@ fn doc_workspace_open_different_library_and_package_names() {
  // check that the cargo config overrides the browser env var
  p.cargo("doc --open")
  .env("BROWSER", "true")
  - .with_stdout_contains("[..]a [CWD]/target/doc/foolib/index.html")
  + .with_stdout_contains("a [CWD]/target/doc/foolib/index.html")
  .run();
  }
  