[Memory-opti:fix leak] fix server leak caused by StaticSimpleEnvironment

src/main/java/li/cil/oc/common/asm/template/StaticSimpleEnvironment.java

@@ -20,7 +20,7 @@
 public final class StaticSimpleEnvironment {
     private StaticSimpleEnvironment() {}
 
-    private static final Map<Environment, Node> nodes = new HashMap<Environment, Node>();
+    private static final Map<Environment, Node> nodes = new HashMap<>();
 
     public static Node node(final SimpleComponentImpl self) {
         // Save ourselves the lookup time in the hash map and avoid mixing in
@@ -86,4 +86,8 @@ public static void writeToNBT(final SimpleComponentImpl self, NBTTagCompound nbt
             nbt.setTag("oc:node", nodeNbt);
         }
     }
+
+    public static void onServerStopped() {
+      nodes.clear();
+    }
 }

src/main/java/li/cil/oc/util/SideTracker.java

@@ -1,23 +1,14 @@
 package li.cil.oc.util;
 
 import cpw.mods.fml.common.FMLCommonHandler;
-import java.util.Collections;
-import java.util.Set;
 
 public final class SideTracker {
-    private static final Set<Thread> serverThreads =
-            Collections.newSetFromMap(new java.util.WeakHashMap<Thread, Boolean>());
 
-    public static void addServerThread() {
-        serverThreads.add(Thread.currentThread());
-    }
+  public static boolean isServer() {
+    return FMLCommonHandler.instance().getEffectiveSide().isServer();
+  }
 
-    public static boolean isServer() {
-        return FMLCommonHandler.instance().getEffectiveSide().isServer()
-                || serverThreads.contains(Thread.currentThread());
-    }
-
-    public static boolean isClient() {
-        return !isServer();
-    }
+  public static boolean isClient() {
+    return !isServer();
+  }
 }

src/main/scala/li/cil/oc/OpenComputers.scala

@@ -8,6 +8,7 @@ import cpw.mods.fml.common.event._
 import cpw.mods.fml.common.network.FMLEventChannel
 import li.cil.oc.common.IMC
 import li.cil.oc.common.Proxy
+import li.cil.oc.common.asm.template.StaticSimpleEnvironment
 import li.cil.oc.server.command.CommandHandler
 import li.cil.oc.util.ThreadPoolFactory
 import org.apache.logging.log4j.LogManager
@@ -91,6 +92,7 @@ object OpenComputers {
   @EventHandler
   def serverStop(e: FMLServerStoppedEvent): Unit = {
     ThreadPoolFactory.safePools.foreach(_.waitForCompletion())
+    StaticSimpleEnvironment.onServerStopped()
   }
 
   @EventHandler