[usecase-wrt]update test step for AudioPolicy

[Detailed commit message (if have)]
Impacted TCs num(approved): New 0, update 1, deleted 0
Unit test platform: [tizen]
Unit test result summary:Pass 0, Fail 1,Block 0
BUGID:https://crosswalk-project.org/jira/browse/XWALK-2562
Merge pull request #916 from linshen/shenlin/wert/updatepaused

[usecase-wrt]update test step for AudioPolicy