Use cid from context when getting browser name

[azz]

The [browser] parameter for the TeamCity name property was not being filled in in my case. Upon inspection the reason is that the session isn't always at ctx.runner['0'], it is ctx.runner[ctx.cid].

Example ctx:

{ type: 'test:end',
  title: 'c',
  parent: '<name>',
  pending: false,
  file: '<path>.js',
  cid: '1a',
  specs: [ '<path>.js' ],
  event: 'test:end',
  runner: { '1a': { browserName: 'internet explorer' } },
  specHash: '<hash>' }

[mightyaleksey]

Hi,

Actually I didn't think that cid can change. Thank you for your effort!

I'll publish it with the next minor version.