Added -SourceLevel auto to match runtime vm spec version.

Also -SourceLevel auto is now the default, otherwise devmode
would choke on class files it itself compiled.

Change-Id: Ife59a3f5137f0cdd51a9acae99aea4d3a5eae837
(cherry picked from commit 8c5e655445b7bfc60b06f277640f98d7b565eae6)
11 files changed