Allow watch of symbolic links to folders on Unix (#52679)

Allow watch of symbolic links to folders on Unix (#52679)

* Allow watch of symbolic links to folders on Unix

* Add logic to repeat directory tests with symlinks

* Remove whitespace

Co-authored-by: Carlos Sanchez <1175054+carlossanlop@users.noreply.github.com>
* Avoid follow symlinks by default in subdirectories

* Add Symbolic Link tests

* Revert "Add logic to repeat directory tests with symlinks"

This reverts commit 5b44eb0195c2e5824ac375862765ea5a2cdeb0ad.

* Exclude test from win7 and 8.1

* Avoid running Process.Start in iOS, tvOS and MacCatalyst

* Apply suggestions from code review

Co-authored-by: Carlos Sanchez <1175054+carlossanlop@users.noreply.github.com>
Co-authored-by: Carlos Sanchez <1175054+carlossanlop@users.noreply.github.com>