Merge pull request #12194 from tchaikov/wip-unit.cc

test,cmake: turn unit.h into unit.cc to speed up compilation

Reviewed-by: Casey Bodley <cbodley@redhat.com>

diff --cc src/test/CMakeLists.txt
Simple merge

diff --cc src/test/erasure-code/CMakeLists.txt
Simple merge

diff --cc src/test/osd/CMakeLists.txt
Simple merge