[wasm] Refactor import handling for 0xC.

test/mjsunit/wasm/compiled-module-management.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.
 
 // TODO (mtrofin): re-enable ignition (v8:5345)
 // Flags: --no-ignition --no-ignition-staging
 // Flags: --expose-wasm --expose-gc --allow-natives-syntax
 
 load("test/mjsunit/wasm/wasm-constants.js");
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
 
 (function CompiledModuleInstancesAreGCed() {
   var builder = new WasmModuleBuilder();
 
   builder.addMemory(1,1, true);
-  builder.addImport("getValue", kSig_i);
-  builder.addFunction("f", kSig_i)
+  builder.addImport("getValue", kSig_i_v);
+  builder.addFunction("f", kSig_i_v)
     .addBody([
       kExprCallFunction, 0
     ]).exportFunc();
 
   var module = new WebAssembly.Module(builder.toBuffer());
   %ValidateWasmModuleState(module);
   %ValidateWasmInstancesChain(module, 0);
   var i1 = new WebAssembly.Instance(module, {getValue: () => 1});
   %ValidateWasmInstancesChain(module, 1);
   var i2 = new WebAssembly.Instance(module, {getValue: () => 2});
@@ skipping 12 matching lines @@
   assertEquals(2, i2.exports.f());
   i2 = null;
   gc();
   %ValidateWasmModuleState(module);
   var i4 = new WebAssembly.Instance(module, {getValue: () => 4});
   assertEquals(4, i4.exports.f());
   module = null;
   gc();
   %ValidateWasmOrphanedInstance(i4);
 })();