vk_shader_decompiler: Use Visit instead of reimplementing it

ExprCondCode visit implements the generic Visit. Use this instead of
that one.

As an intended side effect this fixes unwritten memory usages in cases
when a negation of a condition code is used.

src/video_core/renderer_vulkan/vk_shader_decompiler.cpp

@@ -2552,29 +2552,7 @@ public:
     }
 
     Id operator()(const ExprCondCode& expr) {
-        const Node cc = decomp.ir.GetConditionCode(expr.cc);
-        Id target;
-
-        if (const auto pred = std::get_if<PredicateNode>(&*cc)) {
-            const auto index = pred->GetIndex();
-            switch (index) {
-            case Tegra::Shader::Pred::NeverExecute:
-                target = decomp.v_false;
-                break;
-            case Tegra::Shader::Pred::UnusedIndex:
-                target = decomp.v_true;
-                break;
-            default:
-                target = decomp.predicates.at(index);
-                break;
-            }
-        } else if (const auto flag = std::get_if<InternalFlagNode>(&*cc)) {
-            target = decomp.internal_flags.at(static_cast<u32>(flag->GetFlag()));
-        } else {
-            UNREACHABLE();
-        }
-
-        return decomp.OpLoad(decomp.t_bool, target);
+        return decomp.AsBool(decomp.Visit(decomp.ir.GetConditionCode(expr.cc)));
     }
 
     Id operator()(const ExprVar& expr) {