使用LayaAir 2.0，游戏在微信开发者工具Android模拟器可以正常运行，在iOS模拟器出现以下报错：
CharRender_Canvas.ctx.fillAndStrokeText is not a function
TypeError: CharRender_Canvas.ctx.fillAndStrokeText is not a function
at CharRender_Canvas.__proto.getCharCanvas (http://127.0.0.1:18647/game/libs/laya.webgl.js:12935:26)
at CharRender_Canvas.__proto.getCharBmp (http://127.0.0.1:18647/game/libs/laya.webgl.js:12882:16)
at CharPages.__proto.getCharBmp (http://127.0.0.1:18647/game/libs/laya.webgl.js:7819:31)
at CharPages.__proto.getChar (http://127.0.0.1:18647/game/libs/laya.webgl.js:7723:16)
at CharBook.__proto._fast_filltext (http://127.0.0.1:18647/game/libs/laya.webgl.js:7220:22)
at CharBook.__proto.filltext (http://127.0.0.1:18647/game/libs/laya.webgl.js:7290:8)
at WebGLContext2D.__proto._fillText (http://127.0.0.1:18647/game/libs/laya.webgl.js:11374:29)
at WebGLContext2D.__proto._fillBorderText (http://127.0.0.1:18647/game/libs/laya.webgl.js:11429:8)
at WebGLContext2D.__proto.fillBorderText (http://127.0.0.1:18647/game/libs/laya.webgl.js:11425:8)
at FillBorderTextCmd.__proto.run (http://127.0.0.1:18647/game/libs/laya.core.js:2515:11)
