[webapi] Update 8 tests for Web Audio API

Impacted tests(approved): new 0, update 8, delete 0
Unit test platform: [Android]
Unit test result summary: pass 8, fail 0, block 0
Merge pull request #1064 from kangxu/kangxu/webapi/tct-webaudio-w3c-tests/updatCase

[webapi] Update 8 tests for Web Audio API