Improve wait for splitapp loaded before trying to execute it

Ie90ac441186fe06be96c4c9348a8d30a4f9acc01 tried to fix a race between when
volume is mounted and when the apps are ready for use. It was still racy,
this fixes properly.

Bug: 135341433
Test: while true; do atest AdoptableHostTest; done
Change-Id: I26e99dbdd1704d4fe99e62a7fc33cf10dc74fe42
1 file changed