Load correct chunks for spawn chunk loading - Fixes #1866

logic was loading the wrong x/z in block coords instead of chunk coords

Spigot-Server-Patches/Async-Chunk-Loading-and-Generation.patch

@@ -562,7 +562,7 @@ index 2021c0d02e..154ab09e0c 100644
  
      public void putAll(Map<? extends Long, ? extends Chunk> map) {
 diff --git a/src/main/java/net/minecraft/server/ChunkProviderServer.java b/src/main/java/net/minecraft/server/ChunkProviderServer.java
-index 186cfda7e4..9cdeb3bfc2 100644
+index 186cfda7e4..781e068770 100644
 --- a/src/main/java/net/minecraft/server/ChunkProviderServer.java
 +++ b/src/main/java/net/minecraft/server/ChunkProviderServer.java
 @@ -0,0 +0,0 @@ public class ChunkProviderServer implements IChunkProvider {
@@ -597,14 +597,15 @@ index 186cfda7e4..9cdeb3bfc2 100644
 +    public List<ChunkCoordIntPair> getSpiralOutChunks(BlockPosition blockposition, int radius) {
 +        List<ChunkCoordIntPair> list = com.google.common.collect.Lists.newArrayList();
 +
++        list.add(new ChunkCoordIntPair(blockposition.getX() >> 4, blockposition.getZ() >> 4));
 +        for (int r = 1; r <= radius; r++) {
 +            int x = -r;
 +            int z = r;
-+            list.add(new ChunkCoordIntPair(blockposition.getX(), blockposition.getZ()));
++
 +            // Iterates the edge of half of the box; then negates for other half.
 +            while (x <= r && z > -r) {
-+                list.add(new ChunkCoordIntPair(blockposition.getX() + x, blockposition.getZ() + z));
-+                list.add(new ChunkCoordIntPair(blockposition.getX() - x, blockposition.getZ() - z));
++                list.add(new ChunkCoordIntPair((blockposition.getX() + (x << 4)) >> 4, (blockposition.getZ() + (z << 4)) >> 4));
++                list.add(new ChunkCoordIntPair((blockposition.getX() - (x << 4)) >> 4, (blockposition.getZ() - (z << 4)) >> 4));
 +
 +                if (x < r) {
 +                    x++;
@@ -2318,7 +2319,7 @@ index a9fffa544f..19ce77c4a3 100644
      }
  
 diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
-index 8dccf94989..75c4592c21 100644
+index fac42f8e5c..59b1628e5a 100644
 --- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
 +++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
 @@ -0,0 +0,0 @@ public final class CraftServer implements Server {