Reset system properties after calling event syps (#729)

Event spies may want to read system properties, which will fail if they are reset
too early. This change makes the behavior consistent with regular Maven.

daemon/src/main/java/org/apache/maven/cli/DaemonMavenCli.java

@@ -242,8 +242,8 @@ public class DaemonMavenCli {
         } catch (ExitException e) {
             return e.exitCode;
         } finally {
-            System.setProperties(props);
             eventSpyDispatcher.close();
+            System.setProperties(props);
             Thread.currentThread().setContextClassLoader(tccl);
         }
     }