Fixes a bug in the test (#21146)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21146
The error was reported by https://our.intern.facebook.com/intern/test/562949965807317?ref_report_id=1837062
The API changed from `a.quantize_linear(...)` to `torch.quantize_linear(a, ...)`
Reviewed By: dskhudia
Differential Revision: D15557418
fbshipit-source-id: 88463e09fdf1f574f1b8128f6a00c2810091cd03
