Merge topic 'ctest-empty-binary'

bcb396996c cmCTestEmptyBinaryDirectoryCommand: turn into a free function
9a5525cae7 cmCTestSleepCommand: implement as free function
f7ed0bd2f3 cmCTestCommand: remove CTestScriptHandler member
1440b05bf1 cmMakefile: invoke callback after command execution

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !9869