create-canvas-context-async: 新增所有 context API

pages/API/create-canvas-context-async/child-canvas.uvue

@@ -15,7 +15,7 @@
       return {
        isCanvasContextNull : false
       }
     },
-  
+
     mounted() {
       this.$nextTick(() => {
         uni.createCanvasContextAsync({

pages/API/create-canvas-context-async/create-canvas-context-async.test.js

@@ -10,7 +10,7 @@ describe('create-canvas-context-async', () => {
   it('page canvas', async () => {
     await page.waitFor(100)
     const data = await page.data()
-    expect(data.isCanvasContextNull).toBe(true)
+    expect(data.testCreateCanvasContextAsyncSuccess).toBe(true)
   })
 
   it('component canvas', async () => {