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/autotoolsprojectmanager/autotoolsbuildsystem.cpp

@@ -93,7 +93,7 @@ void AutotoolsBuildSystem::makefileParsingFinished()
     }
 
     auto newRoot = std::make_unique<ProjectNode>(project()->projectDirectory());
-    for (const QString &f : qAsConst(m_files)) {
+    for (const QString &f : std::as_const(m_files)) {
         const Utils::FilePath path = Utils::FilePath::fromString(f);
         newRoot->addNestedNode(std::make_unique<FileNode>(path,
                                                           FileNode::fileTypeForFileName(path)));