[webapi][2439] improve some cases to match the latest spec

- Change readyState from number to string and change remotePort from string to number.
- delete 5 redundant cases according to the latest spec.

Impacted tests(approved): new 0, update 5, delete 5
Unit test platform: [Tizen IVI][Android]
Unit test result summary: pass 5, fail 0, block 0