Don't throw when loom was unable to stop the worker, as it may have a…

…lready been stopped by Gradle.

src/main/java/net/fabricmc/loom/task/GenerateSourcesTask.java

@@ -553,7 +553,7 @@ private void doWork(@Nullable IPCServer ipcServer, Path inputJar, Path outputJar
 				boolean stopped = WorkerDaemonClientsManagerHelper.stopIdleJVM(getWorkerDaemonClientsManager(), jvmMarkerValue);
 
 				if (!stopped && ipcServer.hasReceivedMessage()) {
-					throw new RuntimeException("Failed to stop decompile worker JVM");
+					LOGGER.info("Failed to stop decompile worker JVM, it may have already been stopped?");
 				}
 			}
 		}