Fixes in the accessibility gesture dispatching.

1. The gesture dispatcher thread was not waiting in a loop
   that check for complete initialization. Therefore is was
   susceptible to missed signals and unexpected interrupts.

2. In the gesture processing message handle the interaction id
   was reading the wrong message argument.

bug:5932640

Change-Id: Ic65ecc01a7fe7d43929c6c07d0759ae9001cf515