Put back WSL on Windows CI; pare down debug info

This undoes "Temporarily don't install WSL system to test xfail"
(dabd2fb). It keeps Debian as the distribution. (Although the Debian
WSL system installs pretty fast already, it may still make sense to
try switching to Alpine in the future. But that might need to wait
until Vampire/setup-wsl#50 is fixed.)

This also removes most of the commands in the WSL debugging step,
since the related machinery in test_index.py (_WinBashStatus) seems
to be in okay shape, condenses the smaller number of commands that
are retained there, and makes much less extensive reduction in the
general version and platform information commands as well. This is
to make workflow output easier to read, understand, and navigate.

.github/workflows/cygwin-test.yml

@@ -70,9 +70,7 @@ jobs:
         command -v git python
         git version
         python --version
-        python -c 'import sys; print(sys.platform)'
-        python -c 'import os; print(os.name)'
-        python -c 'import git; print(git.compat.is_win)'  # NOTE: Deprecated. Use os.name directly.
+        python -c 'import os, sys; print(f"sys.platform={sys.platform!r}, os.name={os.name!r}")'
 
     - name: Test with pytest
       run: |

.github/workflows/pythonpackage.yml

@@ -35,6 +35,12 @@ jobs:
         python-version: ${{ matrix.python-version }}
         allow-prereleases: ${{ matrix.experimental }}
 
+    - name: Set up WSL (Windows)
+      if: startsWith(matrix.os, 'windows')
+      uses: Vampire/setup-wsl@v2.0.2
+      with:
+        distribution: Debian
+
     - name: Prepare this repo for tests
       run: |
         ./init-tests-after-clone.sh
@@ -62,29 +68,15 @@ jobs:
         command -v git python
         git version
         python --version
-        python -c 'import sys; print(sys.platform)'
-        python -c 'import os; print(os.name)'
-        python -c 'import git; print(git.compat.is_win)'  # NOTE: Deprecated. Use os.name directly.
+        python -c 'import os, sys; print(f"sys.platform={sys.platform!r}, os.name={os.name!r}")'
 
     # For debugging hook tests on native Windows systems that may have WSL.
-    - name: Show where bash.exe may be found
+    - name: Show bash.exe candidates (Windows)
       if: startsWith(matrix.os, 'windows')
       run: |
         set +e
-        type -a bash.exe
-        python -c 'import shutil; print(shutil.which("bash.exe"))'
-        bash.exe --version
-        python -c 'import subprocess; p = subprocess.run(["bash.exe", "--version"]); print(f"result: {p!r}")'
-        bash.exe -c 'echo "$BASH"'
-        python -c 'import subprocess; p = subprocess.run(["bash.exe", "-c", """echo "$BASH" """]); print(f"result: {p!r}")'
-        bash.exe -c 'echo "$BASH_VERSION"'
-        python -c 'import subprocess; p = subprocess.run(["bash.exe", "-c", """echo "$BASH_VERSION" """]); print(f"result: {p!r}")'
-        bash.exe -c 'printenv WSL_DISTRO_NAME'
-        python -c 'import subprocess; p = subprocess.run(["bash.exe", "-c", "printenv WSL_DISTRO_NAME"]); print(f"result: {p!r}")'
-        bash.exe -c 'ls -l /proc/sys/fs/binfmt_misc/WSLInterop'
-        python -c 'import subprocess; p = subprocess.run(["bash.exe", "-c", "ls -l /proc/sys/fs/binfmt_misc/WSLInterop"]); print(f"result: {p!r}")'
-        bash.exe -c 'uname -a'
-        python -c 'import subprocess; p = subprocess.run(["bash.exe", "-c", "uname -a"]); print(f"result: {p!r}")'
+        bash.exe -c 'printenv WSL_DISTRO_NAME; uname -a'
+        python -c 'import subprocess; subprocess.run(["bash.exe", "-c", "printenv WSL_DISTRO_NAME; uname -a"])'
       continue-on-error: true
 
     - name: Check types with mypy