Import relay requires pytest

1

Looks like import relay needs pytest

  File "./compile-vm.py", line 5, in <module>
    from tvm import relay
  File "/root/workplace/tvm/python/tvm/relay/__init__.py", line 46, in <module>
    from .op import contrib
  File "/root/workplace/tvm/python/tvm/relay/op/contrib/__init__.py", line 21, in <module>
    from .arm_compute_lib import *
  File "/root/workplace/tvm/python/tvm/relay/op/contrib/arm_compute_lib.py", line 25, in <module>
    from tvm.relay.testing.temp_op_attr import TempOpAttr
  File "/root/workplace/tvm/python/tvm/relay/testing/__init__.py", line 28, in <module>
    from tvm.testing import enabled_targets
  File "/root/workplace/tvm/python/tvm/testing.py", line 61, in <module>
    import pytest
ModuleNotFoundError: No module named 'pytest'
2

This PR is addressing this