Bug 1137483 - Replace back actions with Solo.goBack in testInputUrlBar. r=me

This caused some test failures (see comment 34) - I filed bug 1161820 to
prevent this issue in other tests.

--HG--
extra : rebase_source : a90bf758566bad2babedc42b911c3bf7ef79da91

mobile/android/tests/browser/robocop/testInputUrlBar.java

@@ -88,10 +88,10 @@ public final class testInputUrlBar extends BaseTest {
         assertUrlBarText("uv");
 
         // Dismiss the VKB
-        mActions.sendSpecialKey(Actions.SpecialKey.BACK);
+        mSolo.goBack();
 
         // Dismiss editing mode
-        mActions.sendSpecialKey(Actions.SpecialKey.BACK);
+        mSolo.goBack();
 
         waitForText(mStringHelper.TITLE_PLACE_HOLDER);