Set JOB_BASE_NAME consistently for bazel (#62886)
Summary:
It was manually set incorrectly before to pytorch-linux-xenial-py3.6-gcc7-bazel-test-test, which is inconsistent with the rest of our naming scheme.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62886
Reviewed By: driazati
Differential Revision: D30159860
Pulled By: janeyx99
fbshipit-source-id: 4984ec04ee2bcf68b9a57e241ca9f979bfe6398a
