Reduce chem warrior damage vs. wood

The Chem Warrior still does good damage vs. wood, but this will allow more distinction between Flamethrower infantry and Chems. People have been complaining there's no reason not to use chem warriors, which is a claim that has some merit.

Currently, the Chem actually does more damage than Flamethrower vs. wood, which doesn't make a lot of sense. This will make the Flamer do a bit more. Chem damage will be at the level of Bazooka now.

After this change, Flamethrower will have double the economic efficiency in damage per dollar vs. wood. (It already had superior efficiency, but not by much).