Utils: Use an enum indication the possible abort of an dir iteration

The bool is not really clear.

Change-Id: I4ce6412736aec6b1853fd53d4e535ad045748350
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/debugger/gdb/gdbengine.cpp

@@ -1593,7 +1593,7 @@ QString GdbEngine::cleanupFullName(const QString &fileName)
                         QString path = filePath.path();
                         m_baseNameToFullName.insert(name, path);
                     }
-                    return true;
+                    return IterationPolicy::Continue;
                 },
                 {{"*"}, QDir::NoFilter, QDirIterator::Subdirectories});
         }