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/gtest/gtestresult.cpp

@@ -36,7 +36,7 @@
 namespace Autotest {
 namespace Internal {
 
-GTestResult::GTestResult(const QString &id, const QString &projectFile,
+GTestResult::GTestResult(const QString &id, const Utils::FilePath &projectFile,
                          const QString &name)
     : TestResult(id, name), m_projectFile(projectFile)
 {