Stricter validation for popen mode argument on Windows

Context: The ext/standard/tests/file/popen_pclose_error-win32.phpt
test often fails under parallel testing, because the "is not recognized
as an internal or external command" message doesn't actually have a
guaranteed position in the output.

While looking into this, I noticed that this test on Windows tests
something very different (invalid comand) than on Linux (invalid mode).
Here I'm adjusting the Windows popen implementation so it immediately
fails on a `rw` mode, just like it does on Linux.

0 files changed, 0 insertions, 0 deletions