Adds Mortal Spin and Population Bomb

[AlexOn1ine]

Closes #2497 (Credit: Lunos)
Closes #2493

[DizzyEggg]

There were some changes to Triple Kick and multi hit moves in general. I would feel more comfortable merging this PR if we got tests for Triple Kick and moves like Double Kick, Fury Swipes, etc. Also their interactions with Skill Link, when they can miss, when the can't miss, etc.

[AlexOn1ine]

Added Skill Link Tests for EFFECT_MULTI_HIT and some tiny logic for Loaded Dice.

I wasn't able to write tests for Triple Kick and Population Bomb because it doesn't seem you can check their accuracy correctly so @AsparagusEduardo suggested to just add the TO_DO_BATTLE_TEST

[AlexOn1ine]

The tests on github don't pass

- Tests FAILED :       2    Add TESTS='X' to run tests with the defined prefix.
  - Sand Veil increases evasion during sandstorm (1/?).
  - Snow Cloak increases evasion during hail (1/?).

but they pass for me 🤔

[0] Sand Veil prevents damage from sandstorm: PASS
[0] Sand Veil increases evasion during sandstorm: PASS
- Tests PASSED:        2
- Tests TOTAL:         2
- ```

[mrgriffin]

The tests on github don't pass

- Tests FAILED :       2    Add TESTS='X' to run tests with the defined prefix.
  - Sand Veil increases evasion during sandstorm (1/?).
  - Snow Cloak increases evasion during hail (1/?).

but they pass for me thinking

[0] Sand Veil prevents damage from sandstorm: PASS
[0] Sand Veil increases evasion during sandstorm: PASS
- Tests PASSED:        2
- Tests TOTAL:         2
- ```

If you run with make check -j2 do they fail for you? (Yay #3132)
You should get the same output as on CI. (Including the [0] and [1] things)

[AlexOn1ine]

The tests on github don't pass

- Tests FAILED :       2    Add TESTS='X' to run tests with the defined prefix.
  - Sand Veil increases evasion during sandstorm (1/?).
  - Snow Cloak increases evasion during hail (1/?).

but they pass for me thinking

[0] Sand Veil prevents damage from sandstorm: PASS
[0] Sand Veil increases evasion during sandstorm: PASS
- Tests PASSED:        2
- Tests TOTAL:         2
- ```

If you run with make check -j2 do they fail for you? (Yay #3132) You should get the same output as on CI. (Including the [0] and [1] things)

All good

- Tests PASSED:        480
- Tests KNOWN_FAILING: 11
- Tests TO_DO:         40
- Tests TOTAL:         531