build_deprecated combined the testing of deprecated features, and
testing of the build without deprecated features. Also, it violated the
component naming convention by being called build_xxx but running tests.
Replace it by:
* test_default_no_deprecated: check that you can remove deprecated
features from the default build.
* test_full_deprecated_warning: check that enabling DEPRECATED_WARNING
doesn't cause any warning from our own code.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>