Changes:
* CHECK_STRIKES macro now takes a comma-delimited list of strike counts for when units have a different number of strikes for different weapons, and updates the existing usage in the attacks tests
* Fixed a typo in the attacks_zero test
* Adds tests for berserk as a weapon special ability.
Berserk's handling differs from attacks as a weapon special ability:
* A value less than 1 is treated as effectively infinite rounds of combat (undocumented)
* The cumulative attribute is handled differently - in some cases it sums the values instead of using the highest single value whereas for attacks it always uses the highest single value
Also now exclude data/tests/ from scons pot-update since it was hitting the argument limit for number of arguments to a script.
The new tag takes ids instead of needing coordinates. So instead of storing
units or hardcoding values, an attack can be done like this:
```
[test_do_attack_by_id]
attacker=alice
defender=bob
weapon=0
[/test_do_attack_by_id]
```
Add a simpler unit for unit tests than the Elvish Archer / Orcish Grunt
combo, cherry-picked from gfgtdf's PR #7589. This is a unit with a 10x1
melee attack, and 0% defense on all terrains.
Remove the test race's undead_variation=
For testing custom plague abilities, this triggered a warning when
converting to any unit type that doesn't have variation_id=wolf,
restricting tests to using only Walking Corpse and Soulless.
Move the line that includes data/test/scenarios/manual_tests/ below the
line that includes data/test/macros/. This allows a manual test to use
the setup in COMMON_KEEP_A_B_C_D_UNIT_TEST, putting units in the right position
to test combat and leadership abilities.
Also improve comments in data/test/_main.cfg.
There is some WML in data/test/scenarios/ that causes wmlindent to
misbehave (bug #22264 and possibly others awaiting a more thorough
diagnosis), so that subdir is not part of this commit.
