Uncaught exception during initial worldgen deadlocks the game

Uncaught exception during initial worldgen (such as MC-247415) will deadlock the game instead of crashing. This also prevents crash reports from being saved properly. Note that this issue only occurs on some seeds.

Steps to reproduce

1. Trigger MC-247415 or other bugs that crash the game during initial worldgen with the seed -5577097941836652926
2. Observe that the game does not exit and is stuck during worldgen
3. If the game exited, try another seed

Expected Behavior

The game should crash on uncaught exceptions.