fix WebViewActivityTest

one test was failing on Device!
solo.waitForWebElement cannot be used in that context to wait for the webview to appear (it waits for Webelements such as "HTML", "BODY", "DIV",...)

since both tests tested nearly the same, they were merged into one testcase, that can be run on the Emulator
http://jenkins.catrob.at/job/Catroid-single-UI-emulator/111/console