The Child Processes Event: 'exit' has two parameters: code and signal
(https://nodejs.org/api/child_process.html#child_process_event_exit).
One of the two will always be non-null. This helps debugging cases where
code is null.

* fix(browser): allow updating total specs count

This change allows providing the total specs count after the tests have
been started.
The count will be updated in case it has been provided already.
This can be uselful for some adapters where the total specs count can
not be determined before starting the first test.

fix onInfo test case, add new test for total update

Remove `expand-braces` as a dependency. Use `braces.expand` instead
now.

Fixes #3268
Fixes #3269

Remove `combine-lists` as a dependency. Use `_.union` instead now.

Fixes #3265

Append the state of the browser if it gets lost.