Cache mutation trait flags

[CLIDragon]

Summary

Performance "Cache mutation trait flags"

Purpose of change

has_trait_flag took up ~7% of CPU time. It has been reduced to ~1.7%.

Describe the solution

Implement a cache for mutation flags in Character. The implementation was copied from the already existing bio_flag_cache.

Describe alternatives you've considered

None.

Testing

Game runs normally.

Additional context

[PatrikLundell]

A word of caution: adding more data to Character means it takes longer to load or create each Character variable throughout, so it's a net profit only if the reduced access cost for these flags adds up to more than the losses due to the increased weight of Character. The profits on access are easy to make, while the losses are diffuse, and so are hard to quantify. I have no sense of whether it is a problem in this case or not, however.

[CLIDragon]

A word of caution: adding more data to Character means it takes longer to load or create each Character variable throughout, so it's a net profit only if the reduced access cost for these flags adds up to more than the losses due to the increased weight of Character. The profits on access are easy to make, while the losses are diffuse, and so are hard to quantify. I have no sense of whether it is a problem in this case or not, however.

I expect the extra memory cost would be around a dozen JSON flags per Character, which is very small proportional to their current size, while the benefits are large.