twister: add option to ignore skipped tests in reports

With --no-skipped-report, twister will skip over all tests marked as
skipped (filtered) in the junit report.

This is useful for CI where have 1000s of filtered tests that appear in
the report and in some cases cause tools parsing the output to fail or
provide incomplete results.

Fixes #38179

Signed-off-by: Anas Nashif <anas.nashif@intel.com>