gnutls: patch read buffer overrun in the "pre_shared_key" extension

gnutls: patch read buffer overrun in the "pre_shared_key" extension

Pick relevant commit from 3.8.10 release MR [1].
The ME contains referece to undiscoled issue, so any security relevant
patch should be picked.

Binary test file was added as separate file as binary diffs are not
supported.

[1] https://gitlab.com/gnutls/gnutls/-/merge_requests/1979

Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>