Don't recompile apks with speed-profile is the profile is empty

Avoid re-compilation from verify to speed-profile if the profile
is empty. The two are equivalent and we should not waste the
bg-dexopt cycles.

Test: adb shell cmd package compile -r bg-dexopt ...
Bug: 188655918
Change-Id: Iaa999df0b46256a35d0a63e4334e90e340510054