Fix Mercurial tests

Dependencies

• [2] LAJHRL6O Fix tests
• [*] G2ZB6464 first test, not yet in buildprocess
• [*] 4YCF3KBG Concurrent hydra-evaluator

Change contents

• edit in tests/Makefile.am at line 17
  [2.213]

  [5.11287]
  + PYTHONPATH= \