[jsfm] Also enable the promise polyfill on Android (#2704)

Since the internal Promise API may have unpredictable behavior on some
legacy Android devices, so using the js polyfill instead (as iOS does).

Modify the js framework version in package.json, since it has already
been updated in apache/incubator-weex#2669

package.json

@@ -2,7 +2,7 @@
   "name": "weex",
   "version": "0.12.2",
   "subversion": {
-    "framework": "0.29.6",
+    "framework": "0.29.7",
     "transformer": ">=0.1.5 <0.5"
   },
   "description": "A framework for building Mobile cross-platform UI",

runtime/shared/polyfill/promise.js

@@ -24,7 +24,7 @@ const { WXEnvironment } = global
 
 /* istanbul ignore next */
 if (typeof WXEnvironment !== 'undefined'
-  && WXEnvironment.platform === 'iOS'
+  && (WXEnvironment.platform === 'iOS' || WXEnvironment.platform === 'android')
   && !WXEnvironment.__enable_native_promise__) {
   global.Promise = undefined
 }