Only write to cached header in RegionFile if write potentially succeeds (#2294)

Spigot-Server-Patches/Fix-World-isChunkGenerated-calls.patch

@@ -197,7 +197,7 @@ index 0911880c9d..86fb51b90a 100644
      boolean isOutsideOfRange(ChunkCoordIntPair chunkcoordintpair) {
          // Spigot start
 diff --git a/src/main/java/net/minecraft/server/RegionFile.java b/src/main/java/net/minecraft/server/RegionFile.java
-index 2e14d84657..66c8b0307f 100644
+index b0ec9edf67..41f1e15cb0 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 {
@@ -240,7 +240,7 @@ index 2e14d84657..66c8b0307f 100644
          return this.getOffset(chunkcoordintpair) != 0;
      }
 @@ -0,0 +0,0 @@ public class RegionFile implements AutoCloseable {
-         this.writeInt(i); // Paper - Avoid 3 io write calls
+         this.c[j] = i; // Paper - move this to after the write
      }
  
 +    private final int getChunkLocation(ChunkCoordIntPair chunkcoordintpair) { return this.f(chunkcoordintpair); } // Paper - OBFHELPER