streams: Rework stream merging to use ordered-read-streams

[phated]

streams: Rework stream tests to be more stream compliant

What is the purpose of this pull request?

I'm investigating fast-glob for usage in gulp via glob-stream and I noticed that you were using merge2, which does some really unconventional things. This swaps the dependency for ordered-read-streams which has recently been overhauled to be stream/streamx-compliant.

What changes did you make? (Give an overview)

I swapped the merge2 dependency for ordered-read-streams and removed a lot of the event rebinding that was done for merge2. I then updated the tests to show better stream compliance—using things like destroy and Readables that provide data instead of trying to propagate events and rely on specific listeners being bound.