tests: posix: headers: support pthread_setcancelstate() / type()

The function pthread_setcancelstate() has been supported for
some time already in Zephyr. For some reason, it was not being
checked in the "headers" testsuite.

Additionally, check for pthread_setcanceltype() since it was
added in a prior commit.

Signed-off-by: Christopher Friedt <cfriedt@meta.com>