Change CommonFields from a private base class of raw_hash_set to be the first member of the settings_ CompressedTuple so that we can move growth_left into CommonFields.

This allows for removing growth_left as a separate argument for a few functions.

Also, move the infoz() accessor functions to be before the data members of CommonFields to comply with the style guide.

PiperOrigin-RevId: 493918310
Change-Id: I58474e37d3b16a1513d2931af6b153dea1d809c2