Fix animating target can missing show in start transaction.

The last applySurfaceChangesTransaction can trigger
Transition#onTransactionReady if all window report sync finish, but
there won't call prepareSurfaceLocked. However, if the parent of
that window is animating, the window will do performShowLocked and
change the draw state to HAS_DRAWN.
Then when Transition#onTransactionReady, the commitFinishDrawing won't
show that window because the draw state has changed.
Modify the isReadyForDisplay condition that token.isVisible become
necessary, so it only ready after ActivityRecord#commitVisibility

Bug: 347168362
Flag: EXEMPT bugfix
Test: trigger back gesture to task embedded, verify no flikcering on
the opening window.

Change-Id: I4ca978a20185a21fac2ef5d5739a57d5a8f0be0c