tor/changes/parallel_unit_test

  o Minor features (tests):
    - Our "make check" target now runs the unit tests in 8 parallel chunks.
      Doing this speeds up hardened CI builds by more than a factor of two.
      Closes ticket 40098.
Parallelize src/test/test into chunks. First, we introduce a flag to teach src/test/test to split its work into chunks. Then we replace our invocation of src/test/test in our "make check" target with a set of 8 scripts that invoke the first 8th of the tests, the second 8th, and so on. This change makes our "make -kj4 check" target in our hardened gitlab build more than twice as fast, since src/test/test was taking the longest to finish. Closes 40098. 2020-08-12 18:36:54 +02:00			`o Minor features (tests):`
			`- Our "make check" target now runs the unit tests in 8 parallel chunks.`
			`Doing this speeds up hardened CI builds by more than a factor of two.`
			`Closes ticket 40098.`