Fix a bug in creating a prefix string in jit log. (#25051)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25051
In #24355 I factored out a function for creating a prefix in jit_log,
but I made a copypasta error there: the prefix stringstream was
initialized from the input string instead of an empty string.
Test Plan: Imported from OSS
Differential Revision: D16974156
Pulled By: ZolotukhinM
fbshipit-source-id: 014fe0e3366e85e984a6936ec9bb17f571107f6e
Author
Mikhail Zolotukhin
