Port from qAsConst() to std::as_const()

We've been requiring C++17 since Qt 6.0, and our qAsConst use finally
starts to bother us (QTBUG-99313), so time to port away from it
now.

Since qAsConst has exactly the same semantics as std::as_const (down
to rvalue treatment, constexpr'ness and noexcept'ness), there's really
nothing more to it than a global search-and-replace.

Task-number: QTBUG-99313
Change-Id: I88edd91395849574436299b8badda21bb93bea39
Reviewed-by: hjk <hjk@qt.io>

src/plugins/autotest/quick/quicktestparser.cpp

@@ -180,7 +180,7 @@ QList<Document::Ptr> QuickTestParser::scanDirectoryForQuickTestQmlFiles(const Ut
 
     QList<Document::Ptr> foundDocs;
 
-    for (const Utils::FilePath &path : qAsConst(dirs)) {
+    for (const Utils::FilePath &path : std::as_const(dirs)) {
         const QList<Document::Ptr> docs = snapshot.documentsInDirectory(path);
         for (const Document::Ptr &doc : docs) {
             Utils::FilePath fi = doc->fileName();