Revert "Do not set explicitly ALLEN_PROJECT_ROOT"
This reverts MR !1938 (merged)
The failing test in MooreOnline would have to be fixed:
Traceback (most recent call last):
File "/dependencies/Allen/Dumpers/BinaryDumpers/options/allen.py", line 46, in <module>
allen_dir = os.environ["ALLEN_PROJECT_ROOT"]
~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
File "<frozen os>", line 679, in __getitem__
KeyError: 'ALLEN_PROJECT_ROOT'