Fix waitForView cannot find UITableViewCell or label, and results in UITableView on iOS 11

[banjun]

On Xcode 9 & iOS 11, waitForViewWithAccessibilityLabel: @"label text on the cell" returns its UITableView. As commented in the existing code, UITableView is too far in view hierarchy to work with cells level.
On iOS 10, it correctly returns UITableViewCell or UITableViewLabel.

This PR adds testcases to reproduce issue. (After my some inspections, tapViewWithAccessibilityLabel change some unknown states which affects reproducibility, I have added 2 testcases.)
Then this patches the view finding logic by searching -tableViewCell in addition to -view.

element accessibilityContainer for table cells is like below:

iOS 10: UITextAccessibilityElement -> accessibilityContainer = UITableViewCell
iOS 11: UITextAccessibilityElement -> accessibilityContainer = UITableViewCellAccessibilityElement -> accessibilityContainer = UITableView

Thus, we can take UITableViewCell on iOS 10, but we unexpectedly go through to UITableView on iOS 11.

[designatednerd]

Guh, thank you for the detailed explanation, it explains some really odd failures I was seeing (entire table view getting swiped off to the side when trying to swipe to open the delete functionality).

[justinseanmartin]

Please add the equivalent tests for TableViewTests_ViewTestActor.m. We'd like to shift people towards using the new syntax and should have test parity between viewTester and tester.

[justinseanmartin]

Thank you for the contribution and for adding tests that validate the fix! Please squash the commits and address the one piece of feedback and we'll get this merged.

Separately, I'm going to try and get back to having CI working on latest versions of Xcode (#974) so we can ensure this doesn't regress going forward.

[banjun]

Added paired testcases to ViewTestActor and squashed.