Replace the remnants of engine.cpp with better functionality in
FastBootDriver. Particularly, add prolog() and epilog()
callbacks to FastBootDriver for printing actions and their result to
the console. Then clean up the rest of fastboot.cpp to directly use
FastBootDriver.
Test: fastboot works
Change-Id: I0ff01d6a10f75e9dc1c82b46c6e9bb3bc4c68638
This change moves Transport ownership back out of FastBootDriver.
Callers of set_transport must ensure that the previous transport is
destroyed. In addition, deleting a transport now ensures that it is
closed.
Bug: 78793464
Test: fastboot, fuzzy_fastboot works
Change-Id: I8f9ed2f7d5b09fd0820b2677d087a027378f26db
