AI: First Strike / Deathtouch: computer attacks with big creature even though it will be killed by many smaller defenders (who, in turn, will survive)

Concerned abilities: first strike, deathtouch.
The AI doesn't seem to learn from its first mistake, as the bug happens twice in the same game(!).

#### Ex. 1:
A big creature attacks and is blocked by many first-striking (albeit smaller) ones.
As the sum of the defending creatures' power is equal or greater than the attacking creature's toughness, the attacking creature dies. All defenders survive unscratched.

This attack should not have been ordered by the AI...

#### Ex. 2:
A big creature attacks and is blocked by many first-striking, deathtouching (albeit smaller) ones.
As the sum of the defending creatures' power is equal or greater than the attacking creature's toughness, the attacking creature dies. (Plus, they have deathtouch. Even if only one of them had blocked the bigger creature, the attacker would have died anyways.)
All defenders survive unscratched.

This attack should not have been ordered by the AI either...

#### Relevant log lines

##### #L224:

Attacker:
- Matter Reshaper (3/2)

Defenders:
- Plated Sliver (1/2, first strike),
- Striking Sliver (1/2, first strike)

##### #L385:

Attacker:
- Thought-Knot Seer (4/4)

Defenders:
- Plated Sliver (1/2, first strike, flying, haste, deathtouch),
- Striking Sliver (1/2, first strike, flying, haste, deathtouch),
- Cloudshredder Sliver (1/2, first strike, flying, haste, deathtouch),
- Venom Sliver (1/2, first strike, flying, haste, deathtouch)

#### Logfile:
XMage 1.4.43V0 (2020.06.20)
[20200621_194001_Two Player Duel_2.txt](https://github.com/magefree/mage/files/4810481/20200621_194001_Two.Player.Duel_2.txt)

Start by reviewing the attached 20200621_194001_Two Player Duel_2.txt logfile and reproduce the combat scenarios described for Matter Reshaper and Thought-Knot Seer. Trace the AI's attack evaluation for first strike and deathtouch; done means it no longer orders attacks where the attacker dies and the defenders survive.

Written by the indexing model from the issue text.