Refactor the ProcessExecutor.launch(..) method to register a JRE shutdown hook on the ProcessWrapper representing the forked [Java / JVM] process.

Resolves gh-15.

spring-data-geode-test/src/main/java/org/springframework/data/gemfire/tests/process/ProcessExecutor.java

@@ -114,6 +114,7 @@ public abstract class ProcessExecutor {
 		ProcessWrapper processWrapper = new ProcessWrapper(process, ProcessConfiguration.create(processBuilder));
 
 		processWrapper.register((input) -> System.err.printf("[FORK] - %s%n", input));
+		processWrapper.registerShutdownHook();
 
 		return processWrapper;
 	}