test suite, copy over improved test suite from uterus

Now our test suite equals to uterus d60b06ca.
tests, fix renamed TS_EXP_EXIT_CODE variable
tests, fix renamed stdin, stderr, stdout variables
tests, add clean rule for local tempdirs

They are not automatically removed when test fails.
tests, don't use useless option --hash
tests, rewrite convt tests for dt test compiler
tests, remove original convt tests (inclusive test compiler)
tests, don't use head -n-1 (fix BSD)
tests, ignore specific strerrors (BSD)
tests, gdate 2039 problem is probably also a 1970 problem
Merge remote-tracking branch 'rudi/tests' into next

# By Ruediger Meier
# Via Ruediger Meier
* rudi/tests:
  tests, gdate 2039 problem is probably also a 1970 problem
  tests, ignore specific strerrors (BSD)
  tests, don't use head -n-1 (fix BSD)
  tests, remove original convt tests (inclusive test compiler)
  tests, rewrite convt tests for dt test compiler
  tests, don't use useless option --hash
  tests, add clean rule for local tempdirs
  tests, fix renamed stdin, stderr, stdout variables
  tests, fix renamed TS_EXP_EXIT_CODE variable
  test suite, copy over improved test suite from uterus