Kselftest: Add skipgen skipfile support

Just as in f4970555fb ("LTP: Add skipgen skipfile support to ltp"), add
support to kselftest.yaml and kselftest.sh to handle yaml skipfiles that
are parsed using skipgen.

Add the following arguments to kselftest.sh:
    [-b board]
    [-g branch]
    [-e environment]

When the skipfile argument passed via -S ends in ".yaml", a skipfile
will be generated using skipgen. Board, branch, and environment are
optional arguments that get passed to skipgen.

The resulting skipfile is automatically printed to stdout after being
generated.

Change-Id: I90e4140634b961f9bbc9b4164302ea8c9573fcb9
Signed-off-by: Dan Rue <dan.rue@linaro.org>
2 files changed