ptest-runner: Bump to 2.4.3 (92c1b97)

ptest-runner: Bump to 2.4.3 (92c1b97)

Pull small fixed related to secure builds, handling of rc in every ptest
and better tests output when timeout.

Changes,

92c1b97 Do not reset error counter before each test
7de7e2b utils: run_child fix security flags build
6a9fba2 utils.c: get_available_ptests fix security flags compilation
5b8ad9a tests: Ensure that timeouts still print ERROR
d939217 SECURITY.md: Add file

Signed-off-by: Anibal Limon <anibal@limonsoftware.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>