Slow startup on Windows

[OndraM]

It looks like Steward starts slowly on Windows.

Linux, native:

$ time vendor/bin/steward
real    0m0,096s
user    0m0,061s
sys     0m0,037s

Windows, Git BASH, the same machine (but in VirtualBox, which itself slows it down a bit)

$ time vendor/bin/steward
real    0m10,676s
user    0m0,000s
sys     0m0,020s

This should be profiled using eg. blackfire.io to find the root cause. (https://blackfire.io/docs/cookbooks/profiling-cli)

[OndraM]

For comparison phpunit startup time on the same machine on Windows:

$ time ./vendor/bin/phpunit

real    0m0,723s
user    0m0,020s
sys     0m0,020s

[OndraM]

So I managed to do profiling on Windows. This is the result:
https://blackfire.io/profiles/01d6b9cc-4b43-4c07-928b-100508d6baae/graph.

The issue is in searchListeners() method of ListenerInstantiator class - obviously the way we do autodiscovery of listeners is slow on Windows filesystem :-/.