[DDMD] Issue 13190 - Optimizer breaks comparison with zero

@WalterBright The scheduler ignores the conflict between the loop's inc and the condition's psw-setting because the 0x0B (or) instruction is not marked with CFpsw.  This does fix the problem, but is there somewhere better to put this?

https://issues.dlang.org/show_bug.cgi?id=13190