Start the startup-mode test's pager without site-packages

cmd2 lends a new pipeline the terminal for its 0.2s startup check, and a
pager must set its terminal modes within it. Coverage's subprocess hook,
loaded from site-packages, started coverage in the test's Python pager
and slowed its startup enough on a busy macOS runner to miss that
window. Its tcsetattr() then ran in the background and failed with
EINTR. Run the pager with -S so it starts as quickly as less would.

Author: tleonhardt

tests/test_pipeline_job_control.py

@@ -622,7 +622,10 @@ def wait_until(predicate):
         wait_until(lambda: "OUTER> " in transcript)
         os.write(master, f"{shlex.quote(sys.executable)} {shlex.quote(str(application))}\n".encode())
         wait_until(lambda: "TEST>" in transcript)
-        os.write(master, f"help -v | {shlex.quote(sys.executable)} {shlex.quote(str(pager))}\n".encode())
+        # cmd2 lends the terminal for its 0.2s startup check. Like less, the pager must set its modes
+        # within it. -S skips site-packages, where coverage's subprocess hook would otherwise start
+        # coverage in the pager and slow its startup enough on a busy CI runner to miss that window.
+        os.write(master, f"help -v | {shlex.quote(sys.executable)} -S {shlex.quote(str(pager))}\n".encode())
         wait_until(outcome.exists)
         wait_until(lambda: outcome.read_text() != "")
         assert outcome.read_text() == "ok"