Add `hasListeners()`/`hasAnyListeners()` to avoid unnecessary event object instantiation

[PaintNinja]

Adds these static methods:

• Event.hasListeners(bus)
• Event.hasAnyListeners()
• Event.getListenerListStatically()

Transformer changes getListenerListStatically() to grab the same static field that the instance method does.

The hasListeners()/hasAnyListeners() methods check the ListenerList's array size directly - no hashsets or additional memory overhead.

JMH benchmark results:

Benchmark                                                             Mode  Cnt    Score   Error  Units
EventBusBenchmark.testClassLoaderCombined                             avgt   15   42.212 � 0.436  ns/op
EventBusBenchmark.testClassLoaderCombinedHasAnyListeners              avgt   15   34.442 � 0.791  ns/op
EventBusBenchmark.testClassLoaderCombinedHasListeners                 avgt   15    5.480 � 0.042  ns/op
EventBusBenchmark.testModLauncherCombined                             avgt   15   41.072 � 0.339  ns/op
EventBusBenchmark.testModLauncherCombinedHasAnyListeners              avgt   15   34.047 � 0.224  ns/op
EventBusBenchmark.testModLauncherCombinedHasListeners                 avgt   15    5.510 � 0.042  ns/op
EventBusBenchmarkNoLoader.testNoLoaderCombined                        avgt   15  170.711 � 3.025  ns/op
EventBusBenchmarkNoLoader.testNoLoaderCombinedHasAnyListeners         avgt   15   12.390 � 0.046  ns/op
EventBusBenchmarkNoLoader.testNoLoaderCombinedHasListeners            avgt   15    5.319 � 0.067  ns/op

jmh-log.txt jmh_results.txt