[Android] Add test case for onJavascriptCloseWindow().

This patch is to add test case about onJavascriptCloseWindow().
Load a html, it will call "window.close()", then
onJavascriptCloseWindow() will be called. The called flag will be
marked with the help of TestHelperBridge. Get this flag and compare
it with the expected result.
Merge pull request #1995 from wuhengzhi/onJavascriptCloseWindow_test

[Android] Add test case for onJavascriptCloseWindow().