Various Plugins: Simplify return QStringList statements

Change-Id: Id014225851e6b9f8436387c681bea42e5de3b797
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/plugins/autotest/boost/boosttestconfiguration.cpp

@@ -46,7 +46,7 @@ static QStringList interfering(InterferingType type)
             return QString("BOOST_TEST_" + item).toUpper();
         });
     }
-    return QStringList();
+    return {};
 }
 
 static QStringList filterInterfering(const QStringList &provided, QStringList *omitted)