Edge cases for SummaryReporter

[gian1200]

As described in #2810, I'm currently having issues using SummaryReporter when using nested suites. However, when trying to build a PR with a fix I noticed that SummaryRerporter is built on top of a Mocha behavior (which always create an "invisible root suite").

I understand that this behavior can be desirable when tests (it) are not defined within a suite (describe). However:

• Is this behavior also expected for tests defined inside a suite?
• Is this behavior expected from other runners (e.g. Jasmine)? Currently not working as expected

Also, for those testFiles that (for some reason) doesn't have a suite or a test defined, what is the expected behavior, to print something or nothing at all? As a general suggestion, could all results be printed within the testFile name (as a parent); with browser name at the top of it? Something like:

pass-nested-suites.test.js [Chrome]
 Root suite test
  𐄂  test 1
  ✓ test 2
  Nested suite test
   𐄂  test 3
   ✓ test 4
   Nested suite test, level 2
    𐄂  test 5
    ✓ test 6

pass-no-test-or-suite.test.js [Chrome]

pass-another-test.test.js [Chrome]
 ✓ test 1

Or is this ok when no root suite is defined?

[Chrome]
 𐄂  test 1
 ✓ test 2

I have an almost ready PR (https://github.com/gian1200/web/tree/feature/fix-summary-reporter) but wanted some opinions about these edge cases.