recipes-support/ptest-runner: Bump to v2.4.2

Changes,

bcb8280 utils.c: add system data collection when a test gets stuck.
c29240c utils.c: handle test timeouts directly with poll()
d6f509f tests/utils.c: fix a memory corruption in find_word
c10e747 main: Do not return number of failed tests when calling ptest-runner
4958988 utils.c: fix memory leak in run_ptests()
fcfa6a1 clang: clean-ups to avoid -Weverything warnings.
215e52d Makefile: allow using CC env var to pick compiler
fdd233d mem: Simplify memory management
e5e218a mem: Fix memleak for ptest_opts
0dc42eb git: Extend the gitignore

Signed-off-by: Aníbal Limón <anibal.limon@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>