[iOS] Tests with incomplete UIScripts cause flaky crashes under WebKit::RemoteLayerTreeDrawingAreaProxy::commitLayerTree()

[smfr]

47aeeca5223d79b2bae3f8cfb7d60f1ced54d524

[iOS] Tests with incomplete UIScripts cause flaky crashes under WebKit::RemoteLayerTreeDrawingAreaProxy::commitLayerTree()
https://bugs.webkit.org/show_bug.cgi?id=236794
<rdar://89100788>

Reviewed by NOBODY (OOPS!).

If a test calls notifyDone() before all the scripts triggered via `testRunner.runUIScript()` have completed,
then the UI process can be left in a bad state for the next test (for example, the keyboard may still be visible),
and we can hit an assertion in `TestInvocation::runUISideScriptImmediately()` on the next test.

Make a test fail if this happens, so that the error is attributed to the correct test.

Remove some expectations for tests that used to hit this but have been fixed.

* LayoutTests/platform/ios/TestExpectations:
* Tools/WebKitTestRunner/TestInvocation.cpp:
(WTR::TestInvocation::done):