Delete move constructor from TaggedStringStream (#28604)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28604
This isn't used anywhere, and it doesn't work with older libstdc++
because std::ostringstream is not copyable or movable.
Test Plan: Internal android build.
Reviewed By: jamesr66a
Differential Revision: D18099511
fbshipit-source-id: 1ffb49303aa5d7890ca7f057b21886f88c04ce20
