RFR: 8215473: [lworld] Support for substitutability checks in C2

[Roland Westrelin]

Hi Mandy,

> Adding a new ACmpOnValues flag is good.  I'll create a JBS issue for the 
> interpreter change.

I filed JDK-8217714 for that.

> A minor typo:
>
> + experimental(uint, ACmpOnValues, 2, \
> + "0 = regular acmp" \
> + "1 = always false for value, perturbation scheme" \
> + "2 = always false for value" \
> + "3 = substitutably test") \
> + range(0, 3) \
>   
> should be "substitutability test" Thanks Mandy

Thanks! I will fix it before I push the change.

Roland.