tcg/optimize: Use finish_folding as default in tcg_optimize

All non-default cases now finish folding within each function.
Do the same with the default case and assert it is done after.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/optimize.c

@@ -3096,11 +3096,9 @@ void tcg_optimize(TCGContext *s)
             done = true;
             break;
         default:
+            done = finish_folding(&ctx, op);
             break;
         }
-
-        if (!done) {
-            finish_folding(&ctx, op);
-        }
+        tcg_debug_assert(done);
     }
 }