MC-134668: Remove bad synchronized block from FileIOThread

This is causing the main thread to be blocked still.

Spigot-Server-Patches/Chunk-save-queue-improvements.patch

@@ -137,10 +137,21 @@ index f969c036f3..2b0a088a6a 100644
                      NBTCompressedStreamTools.a(nbttagcompound, (DataOutput) dataoutputstream);
                      dataoutputstream.close();
 diff --git a/src/main/java/net/minecraft/server/FileIOThread.java b/src/main/java/net/minecraft/server/FileIOThread.java
-index 8c3537ab8d..170c239b77 100644
+index 8c3537ab8d..3c688f546c 100644
 --- a/src/main/java/net/minecraft/server/FileIOThread.java
 +++ b/src/main/java/net/minecraft/server/FileIOThread.java
 @@ -0,0 +0,0 @@ public class FileIOThread implements Runnable {
+             IAsyncChunkSaver iasyncchunksaver = (IAsyncChunkSaver) this.c.get(i);
+             boolean flag;
+ 
+-            synchronized (iasyncchunksaver) {
++            //synchronized (iasyncchunksaver) { // Paper - remove synchronized
+                 flag = iasyncchunksaver.a();
+-            }
++            //} // Paper
+ 
+             if (!flag) {
+                 this.c.remove(i--);
                  ++this.e;
              }