fixup for launcher/java/JavaPerformance.h:63:21:

  error: invalid use of incomplete type ‘class QDebug’
   63 |             qWarning() << "Unknown garbage collection preset:" << presetString;

Signed-off-by: nadevko <me+oss@nadevko.cc>

--- a/launcher/java/JavaPerformance.h
+++ b/launcher/java/JavaPerformance.h
@@ -19,3 +19,4 @@
 #include <QStringList>
+#include <QDebug>