[webapi][xwalk-3179] Revise timeout to 5000 from 500

- Change timeout to 5000, too short timeout will make test fail

Impacted tests(approved): new 0, update 1, delete 0
Unit test platform: [IVI]
Unit test result summary: pass 1, fail 0, block 0
Merge pull request #1526 from haoxli/webapi/xwalk-3179-2

[webapi][xwalk-3179] Revise timeout to 5000 from 500