BUG : adding parameters for StepLengthSelection in JSON for calatkLDDMMTests

- in commit a8302307b5d88ee320adc8372f5dc3274aa71a7f we corrected the bug in the test by setting the old solver (LineSearchUnconstrained)
- this change adds adequate parameters to use for StepLengthSelection that were not set before in the JSON file (displacement value of 0.005, about half a pixel size, since the spacing of the tested images is 0.01)
- therefore, if you test with the StepLengthSelection Solver, simplifiedShooting and relaxation tests will success (by the way, WAY FASTER than with LineSearchUnconstrained)
- there is still an issue for adjointShooting tests with StepLengthSelection : the displacement value gets to 0 very fast which stops the linesearch.