Extend snprintf negative tests to cover pointer specifiers to prevent possible
invalid handling of %p% from happening again.
./test_progs -t snprintf
#302/1 snprintf/snprintf_positive:OK
#302/2 snprintf/snprintf_negative:OK
#302 snprintf:OK
#303 snprintf_btf:OK
Summary: 2/2 PASSED, 0 SKIPPED, 0 FAILED
Co-developed-by: Nikita Marushkin <hfggklm@xxxxxxxxx>
Signed-off-by: Nikita Marushkin <hfggklm@xxxxxxxxx>
Signed-off-by: Ilya Shchipletsov <rabbelkin@xxxxxxx>