scripts: runner: refactor run() implementation

Have the subclasses implement a do_run() method instead, which run()
delegates to. This will make it possible to handle common
functionality in the superclass before runner-specific methods are
called. It is a prerequisite for tasks like loading the build time
configuration to add device tree awareness.

Signed-off-by: Marti Bolivar <marti@opensourcefoundries.com>
12 files changed