file: Drop error cases added by CMake 3.12.0-rc1 to avoid regressions

Refactoring in !1810 (merged) introduced error diagnostics for argument combinations that were previously accepted. Restore acceptance to avoid regressing projects that used those combinations even if they do not make sense.

Fixes: #18097 (closed)

Warnings:

• Eligible for the 3.12.x branch.

The warnings do not need to be fixed, but it is recommended to do so.

mentioned in issue #18097 (closed)

Do: stage

added workflow:nightly-testing label

Do: merge

removed workflow:nightly-testing label

mentioned in commit 383f29fd

merged

mentioned in commit 221f8aa7