Remove system test stress

There are multiple reasons to remove this test as obsolete:

- The test has no clear failure condition and always succeeds.
- It isn't clear what is the test purpose and what's it's supposed to
  test.
- It isn't part of the test suite either in CI or locally unless it is
  explicitly enabled. As a result, there are many issues which prevent
  the test from being executed caused by various refactoring efforts
  accumulated over time.
- The test has probably never been executed in automated manner, since
  it's not part of the default test suite for over 20 years (see
  ddec026f).
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