[wasm] fix for GC during instantiation.

test/mjsunit/regress/wasm/regression-02862.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: --random-seed=1557792826 --expose-gc --invoke-weak-callbacks --omit-quit --gc-interval=469 --validate-asm
+
+function nop() {}
+var __v_42 = {};
+var __v_49 = {};
+var __v_70 = {};
+var __v_79 = {};
+__v_58 = {
+  instantiateModuleFromAsm: function(text, ffi, heap) {
+    var __v_49 = eval('(' + text + ')');
+    if (nop()) {
+      throw "validate failure";
+    }
+    var __v_79 = __v_49();
+    if (nop()) {
+      throw "bad module args";
+    }
+  }};
+__f_140 = function __f_140() {
+  if (found === expected) {
+    if (1 / expected) return;
+  } else if ((expected !== expected) && (found !== found)) { return; };
+};
+__f_128 = function __f_128() { if (!__f_105()) { __f_125(__f_69(), found, name_opt); } };
+__f_136 = function __f_136(code, type_opt, cause_opt) {
+  var __v_42 = true;
+  try {
+    if (typeof code == 'function') { code(); }
+    else { eval(); }
+    __v_42 = false;
+  } catch (e) {
+    if (typeof type_opt == 'function') { __f_101(); }
+    if (arguments.length >= 3) { __f_128(); }
+    return;
+  }
+};
+__f_101 = function __f_101() { if (obj instanceof type) {obj.constructor; if (typeof __v_57 == "function") {; }; } };
+try {
+__f_128();
+__v_82.__p_750895751 = __v_82[getRandomProperty()];
+} catch(e) {"Caught: " + e; }
+__f_119();
+gc();
+__f_119(19, __f_136);
+__f_119();
+__f_119();
+__f_136(function() {
+  __v_58.instantiateModuleFromAsm(__f_128.toString()).__f_108();
+});
+function __f_119() {
+  "use asm";
+  function __f_108() {
+  }
+  return {__f_108: __f_108};
+}
+__f_119();
+__f_119();
+__f_119();
+function __f_95() {
+}
+__f_119();
+try {
+__f_119();
+__f_135();
+} catch(e) {"Caught: " + e; }
+__f_119();
+__f_119();
+__f_119();
+function __f_105() {
+  "use asm";
+  function __f_108() {
+  }
+  return {__f_108: __f_108};
+}
+__f_119();
+__f_119();
+__f_119();
+__f_119();
+__f_119();
+__f_119();
+__f_119();
+function __f_93(stdlib) {
+  "use asm";
+  var __v_70 = new stdlib.Int32Array();
+__v_70[4294967295]|14 + 1 | 14;
+  return {__f_108: __f_108};
+}
+function __f_135() {
+  var __v_66 = new ArrayBuffer();
+  var __v_54 = new Int32Array(__v_66);
+  var module = __v_58.instantiateModuleFromAsm( __f_93.toString());
+  __f_128();
+}
+(function () {
+})();
+(function () {
+})();
+try {
+(function() {
+      var __v_54 = 0x87654321;
+ __v_66.__f_89();
+})();
+} catch(e) {; }