Summary:
I want to be able parse error stacks in contexts where I have a call stack string but no error object.
This diff changes parseErrorStack to only accept the stack, instead of a whole error object.
Changelog: [Internal]
Reviewed By: motiz88
Differential Revision: D22752048
fbshipit-source-id: b4b1cd58802eefe736130d48a82bc091241a11ee