This is a suggested change I have to simplify the history store code and ideally standardise how we pass information between functions in hs_rec.c. I'm happy for it to be declined if it seems unfeasible or not that helpful.

In essence we have a number of fields we pass all over to pretty much every function in hs_rec they are:

• btree id
• key
• start_time_point
• stop_time_point
• counter

and maybe hs_value.

If we could put those into a WT_HS_RECORD I think it would be a lot cleaner.