[wasm] Inspect right control frames for unreachable flag

test/mjsunit/wasm/wasm-module-builder.js

Index: test/mjsunit/wasm/wasm-module-builder.js
diff --git a/test/mjsunit/wasm/wasm-module-builder.js b/test/mjsunit/wasm/wasm-module-builder.js
index 68de66bf4a530277a249412e7603a8beac196ea1..334a8a14b8e29281e37bae574e5f9add01970c6f 100644
--- a/test/mjsunit/wasm/wasm-module-builder.js
+++ b/test/mjsunit/wasm/wasm-module-builder.js
@@ -97,6 +97,9 @@ class WasmFunctionBuilder {
   }
 
   addBody(body) {
+    for (let b of body) {
+      if (typeof b != 'number') throw new Error("invalid body");
+    }
     this.body = body;
     // Automatically add the end for the function block to the body.
     body.push(kExprEnd);