Disable linux-xenial-cuda10.2 config (#67344)
Summary:
linux-xenial-cuda10.2 and linux-bionic-cuda10.2 are very similar, no
need to run both configs
Moved all auxiliary builds from xenial to bionic
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67344
Reviewed By: seemethere, janeyx99
Differential Revision: D31964850
Pulled By: malfet
fbshipit-source-id: d07ce266c843c7fd69b281e678c4247b0bf6da20
