wasi: support SharedArrayBuffers as memory

This commit adds support for SharedArrayBuffers as the WASI
memory.

Author: cjihrig

lib/wasi.js

@@ -5,6 +5,7 @@
 const { Array, ArrayPrototype } = primordials;
 const { ERR_INVALID_ARG_TYPE } = require('internal/errors').codes;
 const { WASI: _WASI } = internalBinding('wasi');
+const { isAnyArrayBuffer } = require('internal/util/types');
 
 
 class WASI {
@@ -46,7 +47,7 @@ class WASI {
 
     if (memory instanceof WebAssembly.Memory) {
       memory = memory.buffer;
-    } else {
+    } else if (!isAnyArrayBuffer(memory)) {
       throw new ERR_INVALID_ARG_TYPE(
         'options.memory', 'WebAssembly.Memory', memory);
     }

src/node_wasi.cc

@@ -41,7 +41,7 @@ void WASI::New(const FunctionCallbackInfo<Value>& args) {
   CHECK(args[0]->IsArray());
   CHECK(args[1]->IsArray());
   // CHECK(args[2]->IsArray());
-  CHECK(args[3]->IsArrayBuffer());
+  CHECK(args[3]->IsArrayBuffer() || args[3]->IsSharedArrayBuffer());
 
   Environment* env = Environment::GetCurrent(args);
   Local<Context> context = env->context();