fix 4878 by always calling events using bukkit singleton

Spigot-Server-Patches/0054-Add-exception-reporting-event.patch

@@ -239,7 +239,7 @@ index 141a8e31151010e5a0bd8d4661033f109f6a2e67..138c6d707e33cd352aa4b26dfb279c5b
          } finally {
              if (fileinputstream != null) {
 diff --git a/src/main/java/org/bukkit/craftbukkit/scheduler/CraftScheduler.java b/src/main/java/org/bukkit/craftbukkit/scheduler/CraftScheduler.java
-index ffe9cc1011226d604dc5499e7692e9a9a5132b72..343cdb06881fa8b0155b56d29c110bba489f9667 100644
+index ffe9cc1011226d604dc5499e7692e9a9a5132b72..9b6d9373abb59a30c2835ca891282d07559281f5 100644
 --- a/src/main/java/org/bukkit/craftbukkit/scheduler/CraftScheduler.java
 +++ b/src/main/java/org/bukkit/craftbukkit/scheduler/CraftScheduler.java
 @@ -16,6 +16,9 @@ import java.util.concurrent.atomic.AtomicInteger;
@@ -256,7 +256,7 @@ index ffe9cc1011226d604dc5499e7692e9a9a5132b72..343cdb06881fa8b0155b56d29c110bba
                              msg,
                              throwable);
                      }
-+                    task.getOwner().getServer().getPluginManager().callEvent(
++                    org.bukkit.Bukkit.getServer().getPluginManager().callEvent(
 +                        new ServerExceptionEvent(new ServerSchedulerException(msg, throwable, task)));
                      // Paper end
                  } finally {