Fix unstable sapi test, fix GH-9140

Author: mvorisek

sapi/cgi/cgi_main.c

@@ -2271,6 +2271,7 @@ consult the installation file that came with this distribution, or visit \n\
 
 						case 'a':	/* interactive mode */
 							printf("Interactive mode enabled\n\n");
+                            fflush(stdout);
 							break;
 
 						case 'C': /* don't chdir to the script directory */