profile_interval control has unexpected dependance on history_interval

I happened to have these settings while working today:
```
profile_interval = 1
history_interval = 10
```
Instead of writing a profile every step, MESA only wrote one every 10 steps. Right now MESA will only save a profile if it is also writing to the history file for that step. I don't think this is consistent with the documentation of how these controls are supposed to work, so we should probably change it.

Start by locating the code paths that handle profile_interval and history_interval, then reproduce the settings shown in the issue. Confirm that profile output occurs every profile_interval step independently of history output, and add or update coverage for the two different intervals.

Written by the indexing model from the issue text.