check-sr-results: check min/max entries of directories

Add new directives `min-entries' and `max-entries' to the directories
checks. This is better than the documented-but-not-implemented
`can-be-empty' directive.
Use those directives to check the results.

While at it, remove a couple of wildcards to strengthen the checks and
follow the template more closely.

Signed-off-by: Vincent Stehlé <vincent.stehle@arm.com>