Zero width regex match causes heap to run out of memory

[Ingramz]

I noticed that when searching for (?=a) in find-and-replace, it's causing heap to run out of memory via scandal.

Edit by @rsese to add repro steps

1. git clone https://github.com/atom/find-and-replace // I'm at ec58b34a
2. atom --safe find-and-replace
3. Project Find: Show
4. Enable Use Regex
5. Search for (?=a)

[rsese]

Thanks @Ingramz ✌️ Reproduced on macOS 10.12.6 with 1.38.0-nightly20.