wasm: add glue JS code

The file wasm_glue.js was copied from the Go wasm port and was modified,
most importantly to match the TinyGo calling convention.

src/examples/wasm/wasm.js

@@ -3,51 +3,19 @@
 const WASM_URL = '../../../wasm.wasm';
 
 var wasm;
-var logLine = [];
-var memory8;
-
-var importObject = {
-  env: {
-    io_get_stdout: function() {
-      return 1;
-    },
-    resource_write: function(fd, ptr, len) {
-      if (fd == 1) {
-        for (let i=0; i<len; i++) {
-          let c = memory8[ptr+i];
-          if (c == 13) { // CR
-            // ignore
-          } else if (c == 10) { // LF
-            // write line
-            let line = new TextDecoder("utf-8").decode(new Uint8Array(logLine));
-            logLine = [];
-            console.log(line);
-          } else {
-            logLine.push(c);
-          }
-        }
-      } else {
-        console.error('invalid file descriptor:', fd);
-      }
-    },
-  },
-};
 
 function updateResult() {
-  let a = parseInt(document.querySelector('#a').value);
-  let b = parseInt(document.querySelector('#b').value);
-  let result = wasm.exports.add(a, b);
-  document.querySelector('#result').value = result;
+  wasm.exports.update();
 }
 
 function init() {
   document.querySelector('#a').oninput = updateResult;
   document.querySelector('#b').oninput = updateResult;
 
-  WebAssembly.instantiateStreaming(fetch(WASM_URL), importObject).then(function(obj) {
+  const go = new Go();
+  WebAssembly.instantiateStreaming(fetch(WASM_URL), go.importObject).then(function(obj) {
     wasm = obj.instance;
-    memory8 = new Uint8Array(wasm.exports.memory.buffer);
-    wasm.exports.cwa_main();
+    go.run(wasm);
     updateResult();
   })
 }