http/tests/security/mixedContent/insecure-plugin-in-iframe.html is flaky

http/tests/security/mixedContent/insecure-plugin-in-iframe.html is flaky
https://bugs.webkit.org/show_bug.cgi?id=77901

Reviewed by Eric Seidel.

This test fails occationally because of the order of the frame load
callbacks.  Now that we log mixed content errors to the console, we
don't need to dump the frame load callbacks in this test.

* http/tests/security/mixedContent/insecure-plugin-in-iframe-expected.txt:
* http/tests/security/mixedContent/insecure-plugin-in-iframe.html:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@106853 268f45cc-cd09-0410-ab3c-d52691b4dbfc