Fix interpolate trace (#18875)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/10654
The issue is that in tracing `.size` returns an int tensor, and when an int tensor is multiplied by a scalar the int dominates and the scalar gets casted 0.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18875
Differential Revision: D14814441
Pulled By: eellison
fbshipit-source-id: a4e96a2698f2fcbf3ec4b2bb4c43a30250f30ad9
