Get more tests running on Windows (#6537)

* Get rid of system() calls

* Work around '/usr/share/mini' showing up on GitHub Actions (probably due to psutil truncation)

https://github.com/ray-project/ray/runs/722480047?check_suite_focus=true

* Don't check for socket max path length on Windows

* Don't check for socket existence on Windows

* Fix race condition in Windows fate-sharing

* Work around missing .exe extension for Redis tests

* Add more tests to GitHub Actions

Co-authored-by: Mehrdad <noreply@github.com>

.github/workflows/main.yml

@@ -86,6 +86,7 @@ jobs:
         . ./ci/travis/ci.sh build
         . ./ci/travis/ci.sh upload_wheels || true
         . ./ci/travis/ci.sh test_python
+        #. ./ci/travis/ci.sh test_core || true
         . ./ci/travis/ci.sh test_wheels
     - name: Run Clang Include-What-You-Use
       continue-on-error: true