Redo r288270: Hookup mkcsmapper_static and mkesdb_static for 'make clean'

These are only built as part of the top-level 'build-tools' call for
'make buildworld'. They still need to be cleaned during the 'make clean'
treewalks though.

Reported by: markj
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon