This reverts commit 3028832cd35c53937bb6502f74d3ad53646b12a7.
When I created this commit, I made the flawed assumption that spawnTo()
would not be used by plugins. In addition, I was not aware that there
are some usages of spawnTo() in the core which do not check for chunk
usage, such as in Player->showPlayer().
This caused a collection of problems including memory leaks and crashes
due to disconnecting players not removing their references from viewed
entities.
The reverted commit may be the cause of #3178.
dbbe1f2d5c