[wasm] Rework encoding of local declarations.

test/mjsunit/wasm/stackwalk.js

 // 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.
 
 // Flags: --expose-wasm --expose-gc --allow-natives-syntax
 
 load("test/mjsunit/wasm/wasm-constants.js");
 
 function makeFFI(func) {
-  var kBodySize = 6;
+  var kBodySize = 7;
   var kNameFunOffset = kHeaderSize + 24 + kBodySize + 1;
   var kNameMainOffset = kNameFunOffset + 4;
 
   var ffi = new Object();
   ffi.fun = func;
 
   var data = bytesWithHeader(
     // signatures
     kDeclSignatures, 1,
     2, kAstI32, kAstF64, kAstF64, // (f64,f64) -> int
     // -- foreign function
     kDeclFunctions, 2,
     kDeclFunctionName | kDeclFunctionImport,
     0, 0,
     kNameFunOffset, 0, 0, 0,    // name offset
     // -- main function
     kDeclFunctionName | kDeclFunctionExport,
     0, 0,
     kNameMainOffset, 0, 0, 0,   // name offset
     kBodySize, 0,
     // main body
+    kDeclNoLocals,
     kExprCallFunction, 0,       // --
     kExprGetLocal, 0,           // --
     kExprGetLocal, 1,           // --
     // names
     kDeclEnd,
     'f', 'u', 'n', 0,           //  --
     'm', 'a', 'i', 'n', 0       //  --
   );
 
   var module = _WASMEXP_.instantiateModule(data, ffi);
@@ skipping 84 matching lines @@
   var gcer = builder(dogc);
   gcer(7, 7);
 
   for (var i = 0; i < 9; i++) {
     gcer(8, 8);
   }
 }
 
 runTest(makeReentrantFFI);
 runTest(makeFFI);