Frameworks/base: AndroidRuntime standalone preloaded-classes

Change AndroidRuntime::startVM to give the new standalone
preloaded-classes file to the runtime for compilation of images.

Bug: 18305157

(cherry picked from commit 995c62d6abd4b7080e52a60d1bffa32ae4a798a3)

Change-Id: I32a13357893222b25fbce60bf2367c23fb36ab22