Add job to test against old MATLAB (R2009b)

Also shorten test names, because “testsuite_old_matlab” is too long and gets
truncated on the web interface.
3 jobs for master in 1 minute and 13 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #6526
test_matlab

00:00:26

passed #6528
test_octave

00:01:12

failed #6527
test_old_matlab

00:00:02

 
Name Stage Failure
failed
test_old_matlab Test
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{??? Undefined function or variable 'initialize_dseries_class'.

Error in ==> runtest at 18
initialize_dseries_class();
}
>> make: *** [Makefile:11: check-matlab] Error 1
ERROR: Job failed: exit status 1