Prefer empty() to size() when quering containers.
Prefer empty() to size() when quering containers.

Depending on the container, size() might not be O(1). Also empty()
improves readability.

Signed-off-by: Henner Zeller <259ad50fabbfd39355f36ecd6c0afca541ea66ef@acm.org>

alainmarcel/Surelog,chipsalliance/Surelog,alainmarcel/Surelog,alainmarcel/Surelog,chipsalliance/Surelog,alainmarcel/Surelog,chipsalliance/Surelog,chipsalliance/Surelog