Demonstrate that -S works around it

This adds a second test case that passes `-S`, avoiding the
warnings.

(See gitpython-developers/GitPython#2052.)

Author: EliahKagan

test_indirect.py

@@ -12,3 +12,13 @@ def test_subprocess():
         text=True,
     )
     assert proc.stderr == f"{sys.executable=}\n"
+
+
+def test_subprocess_nosite():
+    proc = subprocess.run(
+        [sys.executable, "-S", "reveal_interpreter.py"],
+        check=True,
+        capture_output=True,
+        text=True,
+    )
+    assert proc.stderr == f"{sys.executable=}\n"