Revert D25546409: [PyTorch] Use .sizes() isntead of .size() in cat_serial_kernel_impl
Test Plan: revert-hammer
Differential Revision:
D25546409 (https://github.com/pytorch/pytorch/commit/953f9922ecdeaf313afaead11223ed5ef4cbbead)
Original commit changeset: 196034716b6e
fbshipit-source-id: 0e80f06a98c2842d2f11db7057ffcdcaea85f3bf
