Revert D24042344: [C2] Add string equality operator
Test Plan: revert-hammer
Differential Revision:
D24042344 (https://github.com/pytorch/pytorch/commit/cf48872d28f945d47793f63e19c54dd15bf580f7)
Original commit changeset: c8997c6130e3
fbshipit-source-id: 3d8aec1104a2a59c67ab4b7e77caeaf9fc94ae1d
