[JTC] Improve update methods for tests

[christophfroehlich]

I made an attempt to improve the JTC tests once more.

The ideas come from #697 and #802, and partially fix them.

• state_topic_consistency is now the only test subscribing to the state message publisher.
• All other tests now use the class variables used for building the state message -> no problem with the trylock() of the realtime publisher, which causes problems with tests not running synchronously with the clock, like with [CI] joint_state_broadcaster tests are flaky with coverage build #821
• This enables a new updateControllerAsync test method, which calls the update() of JTC with feasible time/period arguments but asynchronous to the current clock.
• The "old" updateController test method has a sleep_for now, avoiding calling the update() of JTC in the while loop with almost zero duration.
• Both methods run until the end time is reached (<= end_time instead of < end_time). This allows for reducing the thresholds, because the points should be reached exactly, independent of any timing issue.
• Cherry-picking small udpates from [JTC] Accept larger number of joints than command_joints #809 allowing to reactivate the jump-tests.

Overall: The total test time of JTC is decreased by more than 1min. And I hope they are less flaky now.

[bmagyar]

Excellent!

[codecov]

Codecov Report

Merging #858 (6b99228) into master (2854a0b) will increase coverage by 0.08%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #858      +/-   ##
==========================================
+ Coverage   45.51%   45.59%   +0.08%     
==========================================
  Files          40       40              
  Lines        3636     3636              
  Branches     1716     1716              
==========================================
+ Hits         1655     1658       +3     
+ Misses        808      806       -2     
+ Partials     1173     1172       -1     

Flag	Coverage Δ
unittests	45.59% <ø> (+0.08%)	⬆️

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see 1 file with indirect coverage changes