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

test/unittests/wasm/module-decoder-unittest.cc

 // Copyright 2015 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.
 
 #include "test/unittests/test-utils.h"
 
 #include "src/handles.h"
 #include "src/objects-inl.h"
 #include "src/wasm/module-decoder.h"
 #include "src/wasm/wasm-limits.h"
@@ skipping 915 matching lines @@
       SIG_ENTRY_v_v,  // signature entry
       4,              // locals
       3,
       kLocalI32,  // --
       4,
       kLocalI64,  // --
       5,
       kLocalF32,  // --
       6,
       kLocalF64,  // --
-      kExprNop    // body
+      kExprEnd    // body
   };
 
   FunctionResult result =
       DecodeWasmFunction(isolate(), zone(), nullptr, data, data + sizeof(data));
   EXPECT_OK(result);
 
   if (result.val && result.ok()) {
     WasmFunction* function = result.val;
     EXPECT_EQ(0u, function->sig->parameter_count());
     EXPECT_EQ(0u, function->sig->return_count());
@@ skipping 557 matching lines @@
       SECTION(Unknown, 4), 1, 'X', 17,  18,                      // --
       SECTION(Unknown, 9), 3, 'f', 'o', 'o', 5,   6,   7, 8, 9,  // --
       SECTION(Unknown, 8), 5, 'o', 't', 'h', 'e', 'r', 7, 8,     // --
   };
   EXPECT_VERIFIES(data);
 }
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8