Emojis in branch names cause Bamboo to create a huge amount of new branch builds

Affected Version: 5.10.0-m23

Steps to reproduce:

1. Create a branch in a linked repo with an emoji
2. Create a plan that automatically creates new branches

This should create a single new build for the emoji branch, but instead seems to keep spawning off new builds every time the repo is polled.

We saw roughly 1500 builds created per plan that was linked to the problematic repo:

And we saw the number of builds on the whole instance rise steadily over time:

I also found a branch that was created back in 2013 which caused the exact same pattern: