Address recent performance regression

[d-b-w]

Reported in the schrödinger bug tracker as SHARED-7789

Our performance monitoring tests noticed that coordgen got about 10x slower after PR #81. I guess the inner loop of minimization must be hitting the max pretty frequently! We should address that too.

(this doubles the max iterations from before #81, but that's ok because #81 included a tidy refactor that halved the calls to this function)

Before this commit:

slowest:  1.442s
average: 0.044s
# above 0.1s: 566
# above 1s: 9

After this commit:

slowest: 0.151s
average: 0.006s
molecules above 0.1s: 12
molecules above 1s: 0