Fix the bindings for performance.now() and document.*

performance.now() and co. need to be called with the proper this value.

std/assembly/bindings/dom.ts

@@ -229,54 +229,65 @@ export declare namespace document {
    * @param tagName The name of an element.
    */
   @external("env", "document.createElement")
+  @external.js("return document.createElement(tagName);")
   export function createElement(tagName: string /* , options?: ElementCreationOptions */): externref;
   /**
    * Returns a reference to the first HTMLElement object with the specified value of the ID attribute.
    * @param id String that specifies the ID value.
    */
   @external("env", "document.getElementById")
+  @external.js("return document.getElementById(id);")
   export function getElementById(id: string): externref;
   /**
    * Returns a HTMLCollection of the elements in the object on which the method was invoked that have all the classes
    * given by classNames. The classNames argument is interpreted as a space-separated list of classes.
    * @param classNames Gets a collection of objects based on the value of the CLASS attribute.
    */
   @external("env", "document.getElementsByClassName")
+  @external.js("return document.getElementsByClassName(classNames);")
   export function getElementsByClassName(classNames: string): externref;
   /**
    * Gets a collection of HTMLElement objects based on the value of the NAME or ID attribute.
    * @param elementName Gets a collection of objects based on the value of the NAME or ID attribute.
    */
   @external("env", "document.getElementsByName")
+  @external.js("return document.getElementsByName(elementName);")
   export function getElementsByName(elementName: string): externref;
   /** Gets a value indicating whether the object currently has focus. */
   @external("env", "document.hasFocus")
+  @external.js("return document.hasFocus();")
   export function hasFocus(): bool;
   /** Inserts nodes after the last child of node, while replacing strings in nodes with equivalent Text nodes. */
   @external("env", "document.append")
+  @external.js("return document.append(node);")
   export function append(node: externref): void;
   /** Inserts nodes before the first child of node, while replacing strings in nodes with equivalent Text nodes. */
   @external("env", "document.prepend")
+  @external.js("return document.prepend(node);")
   export function prepend(node: externref): void;
   /** Replace all children of node with nodes, while replacing strings in nodes with equivalent Text nodes. */
   @external("env", "document.replaceChildren")
+  @external.js("return document.replaceChildren(node);")
   export function replaceChildren(node: externref): void;
   /**
    * Writes one or more HTML expressions to a document in the specified window.
    * @param content Specifies the text and HTML tags to write.
    */
   @external("env", "document.write")
+  @external.js("return document.write(content);")
   export function write(content: string): void;
   /**
    * Writes one or more HTML expressions, followed by a carriage return, to a document in the specified window.
    * @param content Specifies the text and HTML tags to write.
    */
   @external("env", "document.writeln")
+  @external.js("return document.writeln(content);")
   export function writeln(content: string): void;
 }
 
 export declare namespace performance {
   @external("env", "performance.now")
+  @external.js("return performance.now();")
   export function now(): f64;
 }