Grant Likely authored Mar 10, 2021 and Vincent Stehlé committed Mar 15, 2021

The libyaml implementation is significantly faster than the pure python
YAML parser. If it is present, then use CDumper when dumping the
results.

Signed-off-by: Grant Likely <grant.likely@arm.com>
[Rebased, added conditional.]
Signed-off-by: Vincent Stehlé <vincent.stehle@arm.com>