[ivi-tct][webapi] Fix 2 tests for Audio & Video

Impacted tests(approved): new 0, update 2, delete 0
Unit test platform: [IVI]
Unit test result summary: pass 2, fail 0, block 0
Merge pull request #1413 from yunxiaoxie/canPlayType-null

[ivi-tct][webapi] Fix 2 tests for Audio & Video