test: skip the pwd_shell test on IBMi

On IBMi PASE, the value of pw_shell is always an empty string.

PR-URL: https://github.com/libuv/libuv/pull/2592
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

test/test-get-passwd.c

@@ -38,7 +38,9 @@ TEST_IMPL(get_passwd) {
   ASSERT(pwd.shell == NULL);
 #else
   len = strlen(pwd.shell);
+# ifndef __PASE__
   ASSERT(len > 0);
+# endif
 #endif
 
   len = strlen(pwd.homedir);