[wasm] Enforce that function bodies end with the \"end\" opcode.

test/mjsunit/wasm/indirect-tables.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --expose-wasm
 
 load("test/mjsunit/wasm/wasm-constants.js");
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
 function AddFunctions(builder) {
@@ skipping 425 matching lines @@
 
   // Verify that grow does not alter function behaviors
   for (var j = 0; j < 10; j++) {
     let func = table.get(j);
     assertEquals("function", typeof func);
     assertEquals(j, func());
     assertEquals(j, instances[j].exports.main(j));
   }
 
   let new_builder = new WasmModuleBuilder();
-  new_builder.addExport("wasm", new_builder.addFunction("", kSig_v_v));
+  new_builder.addExport("wasm", new_builder.addFunction("", kSig_v_v).addBody([]));
   new_builder.addImportedTable("x", "table", 20, 30);
   let new_module = new WebAssembly.Module(new_builder.toBuffer());
   let instance = new WebAssembly.Instance(new_module, {x: {table: table}});
   let new_func = instance.exports.wasm;
 
   for (var j = 10; j < 20; j++) {
     table.set(j, new_func);
     let func = table.get(j);
     assertEquals("function", typeof func);
     assertSame(new_func, table.get(j));
   }
   assertThrows(() => table.grow(11));
 })();