Porting human\life fix from Baystation12

- There's really no reason to not have this. That's one loop instead of
four and saves up some processing power. And heavens knows we need
processing power
Revert "Porting human\life fix from Baystation12"

This reverts commit 80fc3ca36a7fca18bc29886dbba7a77e49ffb17a.
Merging reagent check loops

Change directly ported from Baystation12 code. Every bit of improvement
helps

- The four loops used to check for chemicals affecting heart rates have
been consolided into a single loop
Merge pull request #1332 from dylanstrategie/Human-Life

Merging reagent check loops