Android: QV4_SHOW_IR debug output not visible

The debug output from V4 is very useful for tracking down bugs in the JavaScript engine, but on Android it cannot be viewed because it directs the output to stderr, and on Android there is no console.

If the output is redirected to qDebug() instead, then Android will print it to the default debug log, which can be viewed using adb logcat (or directly in the Qt Creator console.)