Remove Y limits if a region has no world

0cb1eea55b311473c9468f608a0090b93cf5de91

Co-Authored-By: Octavia Togami <2093023+octylFractal@users.noreply.github.com>

worldedit-core/src/main/java/com/sk89q/worldedit/regions/AbstractRegion.java

@@ -211,11 +211,11 @@ public abstract class AbstractRegion extends AbstractSet<BlockVector3> implement
     // Sub-class utilities
 
     protected final int getWorldMinY() {
-        return world == null ? 0 : world.getMinY();
+        return world == null ? Integer.MIN_VALUE : world.getMinY();
     }
 
     protected final int getWorldMaxY() {
-        return world == null ? 255 : world.getMaxY();
+        return world == null ? Integer.MAX_VALUE : world.getMaxY();
     }
 
     @Override