CI: extra_args from sanitycheck *.yaml do not propogate to cmake

[finikorg]

extra_args from *.yaml do not go to the build system.

Reproduce
extra_args: "-DDEBUG_PRINTF=1" from samples/philosophers/sample.yaml is lost.

$ sanitycheck -c -M -p native_posix --test samples/philosophers/sample.kernel.philosopher

Output:

...
CMake Warning:
  Manually-specified variables were not used by the project:

    -DDEBUG_PRINTF
...

and

DEBUG   - Calling cmake with arguments: ['-B/home/niko/work/zephyrproject/sanity-out/native_posix/samples/philosophers/sample.kernel.philosopher', '-S/home/niko/work/zephyrproject/zephyr/samples/philosophers', '-DEXTRA_CFLAGS="-Werror ', '-DEXTRA_AFLAGS=-Wa,--fatal-warnings', '-DEXTRA_LDFLAGS="-Wl,--fatal-warnings', '-GUnix Makefiles', '-D-DDEBUG_PRINTF=1', '-DBOARD=native_posix']

[mbolivar-nordic]

I don't think I'm the right assignee.

[nashif]

so, this is not an issue in sanitycheck or west.. The fact that cmake reports about the variable means it was passed correctly to the sample.
Looks like cmake has no idea what to with this and some additional handling is needed in the cmake file, fixed for this sample. If we do not want this to go through cmake then i think we should add

-DEXTRA_CFLAGS="-DDEBUG_PRINTF=1"

instead, not sure yet.

[finikorg]

We can keep this bug to handle also other parameters in extra_args.