radv: Don't optimize after lowering FS inputs

Currently this is done rather late in radv, after lowering booleans, so it isn't safe to run additional optimizations that may add e.g. 1-bit booleans. We could move the lowering parts earlier, but since right now we only lower FS inputs and by this point all indirects have been lowered away, there's no reason we should need to optimize anything.

One shader from Devil May Cry 5 was getting optimized, but only because the optimization loop was working on 32-bit booleans which revealed an opportunity that was hidden with 1-bit booleans, and we generated a 1-bit boolean which is invalid.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111092 Fixes: 118a66df