Some EarlGrey tests where a field in WKWebView brings up the keyboard (i.e. tapping a text field) have synchronization problems.

We should see if it's something our utilities need to fix to synchronize with WKWebView, or if it's an EG bug, which may be independent of WKWebView.

This came up in a code review for testBrowsingPostEntryWithKeyboard in browsing_egtest.mm, where synchronization is disabled when the keyboard is presented.