Fix SafeNBTCopy#hasKey semantics

Fixes hasKey to check that a key actually exists, while retaining the
option to scream at keys which are requested which haven't been marked as
needing to be copied

Spigot-Server-Patches/0488-Fix-Non-Full-Status-Chunk-NBT-Memory-Leak.patch

@@ -16,7 +16,7 @@ We further improve it by making a copy of the nbt tag with only the memory
 it needs, so that we dont have to hold a copy to the entire compound.
 
 diff --git a/src/main/java/net/minecraft/server/ChunkRegionLoader.java b/src/main/java/net/minecraft/server/ChunkRegionLoader.java
-index f18cb4aedc4a6536bf45db591b6d2b64cefce676..c27078630bffe1b2493b42c9ae4431fb1cc5ca09 100644
+index f18cb4aedc4a6536bf45db591b6d2b64cefce676..5eb14b330d3f175e22650f292aa6c040f24e9492 100644
 --- a/src/main/java/net/minecraft/server/ChunkRegionLoader.java
 +++ b/src/main/java/net/minecraft/server/ChunkRegionLoader.java
 @@ -156,15 +156,9 @@ public class ChunkRegionLoader {
@@ -38,7 +38,7 @@ index f18cb4aedc4a6536bf45db591b6d2b64cefce676..c27078630bffe1b2493b42c9ae4431fb
          } else {
              ProtoChunk protochunk = new ProtoChunk(chunkcoordintpair, chunkconverter, achunksection, protochunkticklist, protochunkticklist1, worldserver); // Paper - Anti-Xray - Add parameter
  
-@@ -270,6 +264,48 @@ public class ChunkRegionLoader {
+@@ -270,6 +264,50 @@ public class ChunkRegionLoader {
              return new InProgressChunkHolder(protochunk1, tasksToExecuteOnMain); // Paper - Async chunk loading
          }
      }
@@ -61,8 +61,10 @@ index f18cb4aedc4a6536bf45db591b6d2b64cefce676..c27078630bffe1b2493b42c9ae4431fb
 +
 +        @Override
 +        public boolean hasKey(String s) {
-+            if (this.keys.contains(s)) {
++            if (super.hasKey(s)) {
 +                return true;
++            } else if (keys.contains(s)) {
++                return false;
 +            }
 +            throw new IllegalStateException("Missing Key " + s + " in SafeNBTCopy");
 +        }