various small tests ...

[alaingdl]

OK, this is a merging of various codes in GDL syntax for tests :

• test_xyztick_get.pro tests [xyz]tick_get for PLOT & SURFACE, with various combinations of fields and ranges
  (@GillesDuvert that shows PR close #1781 (TICK_GET error) #1785 is not the definitive one)
• test_operators.pro tests /=, *=, +=, -=. Might be redundant with test_indepth_basic_functions.pro
• gdl_version.pro does manages the new version schema strip first char of version string for !GDL.RELEASE if it is "v" #1780 (for naming convention in i.e. bench out files)
• test_foreach.pro merges some tests related to FOREACH (SF 273, 630 and test_bug_3288652.pro (removed outside)
• bench_loops.pro

[alaingdl]

• correcting ISA() and SIZE() for HASH() & LIST() (LIST() and HASH() don't have the rigth SIZE(/n_dim) #1725)
• wrong name in the final message of test_xyztick_get.pro
• new entry in test_isa.pro for missing /file keyword

[GillesDuvert]

test_operators.pro tests /=, *=, +=, -=. Might be redundant with test_indepth_basic_functions.pro
yes, operators are there for "completion" but the real test that visit every possible line of code is indeed test_indepth_basic_functions.pro.
probably not worth the work to clean those duplicates.
and test_indepth_basic_functions.pro is really test_indepth_all_operators.pro.

[GillesDuvert]

test_xyztick_get.pro has been invaluable in realizing AutoTick was wrong, thanks @alaingdl .