AutoTest: Use Utils::FilePath for files and directories

Still some missing bits as some QString members had different meanings
depending on their context.

Change-Id: Ib48eab54498974a26bbd5123cbffeefee5f7e79c
Reviewed-by: hjk <hjk@qt.io>

src/plugins/autotest/boost/boosttestparser.h

@@ -45,7 +45,7 @@ class BoostTestParser : public CppParser
 public:
     explicit BoostTestParser(ITestFramework *framework) : CppParser(framework) {}
     bool processDocument(QFutureInterface<TestParseResultPtr> futureInterface,
-                         const QString &fileName) override;
+                         const Utils::FilePath &fileName) override;
 };
 
 } // namespace Internal