longpress on UITextField gets stuck with app state tracker not becoming idle on 9.3

We saw this happen a lot in Chrome, and were able to reproduce it in the EarlGrey FunctionalTest app.

When long pressing a UITextField, the next step fails about every time on device and less than one third of the time on simulator. The failure is because the AppStateTracker doesn't become idle. This was all on iOS 9.3. I don't know if it is iOS 9.3 only, or just less common on 10.0+.

I seemingly was able to work around it by removing a call to clearTouches in GREYTouchInjector. I haven't tested exhaustively to verify that it works 100%.

Reproduce the long-press UITextField failure in the EarlGrey FunctionalTest app on iOS 9.3, then inspect GREYTouchInjector and its clearTouches call alongside the AppStateTracker behavior. Done means the next step no longer fails because AppStateTracker remains non-idle, with behavior checked on device and simulator.

Written by the indexing model from the issue text.