[jit] define equality for IValue (#34986)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/34986
Previously we were reluctant to define equality for IValues, as it's not
totally straightforward. But the vacuum this created basically forced
people to define their own equality comparisons for their own purposes.
We have at least 3 in PyTorch itself, and 2 others outside that I know
of.
These implementations are generally wrong, so we should just bite the
bullet and define equality canonically.
Test Plan: Imported from OSS
Differential Revision: D20537901
Pulled By: suo
fbshipit-source-id: 8d770a31bf6de6f3b38f9826bf898d62c0ccf34e
