[WebView][Non-ACR] Fix some TCs due to Chromium upstream change
This patch fixes 2 TCs due to Chromium upstream change.
1. Tizen.WebView.Tests.SettingsTests.ScriptsCanOpenWindows_READ_WRITE
Default value of new window policy is 'Allowed', so it is appropriate to
perform the negative case first.
2. Tizen.WebView.Tests.WebViewTests.StopLoading_CHANGE_STATUS
Error event is no longer occurred by the user's stop request, this patch
checks only stop request at the start of loading.
Change-Id: I6fdb91e92beb8920753cc666074360bfd760c93d
Signed-off-by: yh106.jung <yh106.jung@samsung.com>