Drop Close region files patch, doesn't add any value.

Upon further knowledge of the system, it is known that region files
are closing properly, as well as this didn't help native memory use anyways.

This patch also caused issues compiling on a newer JDK being able to
release the jar to java 8 users.

Spigot-Server-Patches/Cleanup-Region-Files-Direct-Memory-on-close.patch

@@ -1,84 +0,0 @@
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Aikar <aikar@aikar.co>
-Date: Mon, 4 May 2020 00:38:13 -0400
-Subject: [PATCH] Cleanup Region Files Direct Memory on close
-
-Mojang was semi leaking native memory here by relying on finalizers
-to clean up the direct memory.
-
-Finalizers have no guarantee on when they will be ran, and since this is
-old generation memory, it might be a while before its called.
-
-diff --git a/src/main/java/net/minecraft/server/RegionFile.java b/src/main/java/net/minecraft/server/RegionFile.java
-index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
---- a/src/main/java/net/minecraft/server/RegionFile.java
-+++ b/src/main/java/net/minecraft/server/RegionFile.java
-@@ -0,0 +0,0 @@ public class RegionFile implements AutoCloseable {
-     private final FileChannel dataFile;
-     private final java.nio.file.Path d;
-     private final RegionFileCompression e;
--    private final ByteBuffer f;
-+    private final ByteBuffer f; private ByteBuffer getFileBuffer() { return f; } // Paper - clean up direct buffers on close
-     private final IntBuffer g;
-     private final IntBuffer h;
-     private final RegionFileBitSet freeSectors;
-@@ -0,0 +0,0 @@ public class RegionFile implements AutoCloseable {
-         }
-         } finally { // Paper start - Prevent regionfiles from being closed during use
-             this.fileLock.unlock();
-+            if (getFileBuffer().isDirect()) cleanDirectByteBuffer(getFileBuffer()); // Paper - clean up direct buffers on close
-         }
-         } // Paper end
- 
-     }
-+    // Paper start
-+    private static int getVersion() {
-+        String version = System.getProperty("java.version");
-+        if(version.startsWith("1.")) {
-+            version = version.substring(2, 3);
-+        } else {
-+            int dot = version.indexOf(".");
-+            if(dot != -1) { version = version.substring(0, dot); }
-+        } return Integer.parseInt(version);
-+    }
-+    static java.lang.reflect.Method unsafeClean;
-+    static sun.misc.Unsafe unsafe = com.destroystokyo.paper.utils.UnsafeUtils.getUnsafe();
-+    static java.util.function.Consumer<ByteBuffer> cleaner;
-+    static {
-+        try {
-+            if (unsafe != null) {
-+                unsafeClean = unsafe.getClass().getMethod("invokeCleaner", ByteBuffer.class);
-+                if (unsafeClean != null) {
-+                    cleaner = (buf) -> {
-+                        try {
-+                            unsafeClean.invoke(unsafe, buf);
-+                        } catch (Exception ex) {
-+                            com.destroystokyo.paper.util.SneakyThrow.sneaky(ex);
-+                        }
-+                    };
-+                    LOGGER.info("[RegionFile] Using Java 9+ invokeCleaner DirectByteBuffer cleanup method");
-+                }
-+            }
-+        } catch (java.lang.NoSuchMethodException e) {}
-+        if (cleaner == null && getVersion() <= 8) {
-+            cleaner = (buf) -> {
-+                ((sun.nio.ch.DirectBuffer) buf).cleaner().clean();
-+            };
-+            LOGGER.info("[RegionFile] Using Java 8 DirectByteBuffer cleanup method");
-+        }
-+    }
-+    public static void cleanDirectByteBuffer(ByteBuffer toBeDestroyed) {
-+        try {
-+            if (cleaner != null) {
-+                cleaner.accept(toBeDestroyed);
-+            }
-+        } catch (Exception ex) {
-+            LOGGER.warn("Failed automatically cleaning DirectByteBuffer");
-+            ex.printStackTrace();
-+            cleaner = null;
-+        }
-+    }
-+    // Paper end
- 
-     private void c() throws IOException {
-         int i = (int) this.dataFile.size();