WebView: deflake WebViewSslTest for TLS 1.3 bug

This deflakes WebViewSslTest.testIgnoreClientCertRequest, which was
failing due to another side effect of the same TLS 1.3 race condition:
if we lose the race for one page load (i.e., receive ERROR_CONNECT),
then we won't call onReceivedClientCertRequest() for the subsequent page
load.

This is a minimal patch to fix the flakiness, since we'll need to
cherrypick this solution to the Android Q branch.

Bug: 172407344
Bug: 172332767
Test: atest --rerun-until-failure=40 \
      CtsWebkitTestCases:WebViewSslTest#testIgnoreClientCertRequest
Change-Id: Iee8a8a17a48574c5b369a6fc6f154f480f63c35e