Merge topic 'simplify-backtrace'

61c46c95ae cmListFileContext: Simplify explicit rule-of-five members
d0ceb409ff cmListFileBacktrace: Remove unused "Depth" method
7b677dbb92 cmListFileBacktrace: Remove unused "bottom" entry
56dc22d488 cmMessenger: Make relative path conversion more explicit
c749982c13 cmTargetPropertyComputer: Simplify by restoring use of cmMakefile
3d378541bb cmMessenger: Adopt backtrace printing functions

Acked-by: Kitware Robot <kwrobot@kitware.com>
Tested-by: buildbot <buildbot@kitware.com>
Merge-request: !6794