Atest plugin: add error handling when user input wrong argument.

Bug: 144140052
Test: 1. In atest_plugin folder: ./gradlew :runIde
      2. Open a project which not in Android directory.
      3. Launch Atest tool window, click the run button.
         It should show the error dialog.

Change-Id: I308ea5737f85a011f0dfba166fde04df334fa38f
9 files changed