Fix players spawning above portals. Fixes BUKKIT-3542.

Vanilla does not check for blocks in which the player could
suffocate when changing dimension, so portals will happily spawn
players in blocks when using a portal under certain
circumstances. However, we currently check for these instances
and move the player up until they will not suffocate. This means
that players can sometimes be taken to above the target portal,
making it seem as if a portal was not created. Instead, we now
disable this suffocation check when moveToWorld is called from
changeDimension, mirroring vanilla behavior more accurately.

src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java

@@ -389,7 +389,7 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
             if (getHandle().activeContainer != getHandle().defaultContainer){
                 getHandle().closeInventory();
             }
-            server.getHandle().moveToWorld(entity, toWorld.dimension, true, to);
+            server.getHandle().moveToWorld(entity, toWorld.dimension, true, to, true);
         }
         return true;
     }