Tests: updated try_run() to rely on nginx "-e". The "-e" command line option introduced in nginx 1.19.5 is now used to print error line on startup failures with TEST_NGINX_VERBOSE set. This change replaces a previous approach (a1874249496d) compatible with pre-1.19.5 nginx versions that used to redirect stderr to file. Hence, "-e" compatibility is removed. As a side effect, this fixes temporary directory removal on win32 left on startup failures because the "stderr" file was kept open.