Players respawn at bedrock level when the default game mode is Adventure

Players can now respawn at bedrock level when:

• The default gamemode is set to adventure mode.

• The chunk with the world spawnpoint (doesn’t matter where it was set) is unloaded

Steps to reproduce:

1. Create a new world with cheats enabled

2. /defaultgamemode adventure

3. /tp 5000 100 5000

4. Wait a few seconds to ensure the chunks at the spawnpoint are unloaded

5. /kill and click respawn

Expected result:
You respawn at the surface of the world at the X/Z of the world spawn.

Actual result:

You respawn at the bottom of the world (inside bedrock layers) at the X/Z of the world spawn.