Merge topic 'backport-pkg-root-var' into release-4.0

ab0a44a0a0 find_package: Fix regression on `<PackageName>_ROOT` relative to CWD
d029b828b2 find_package: Avoid repeating search for lower-case .cps file
fc4d238d7a Tests: Match RunCMake.find_package-CPS version candidates more precisely

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !11277