Consistently give qbs groups a name.

These nicely show up in the project tree in Qt Creator then.

Change-Id: I9782f5953d61940e6c2a0f61f07bb15aaeba49d9
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

src/plugins/qmljstools/qmljstools.qbs

@@ -74,6 +74,7 @@ QtcPlugin {
     ]
 
     Group {
+        name: "Tests"
         condition: Defaults.testsEnabled(qbs)
         files: ["qmljstools_test.cpp"]
     }