Relicense most GPL-2.0-only test files to GPL-2.0-or-later

All contributors are recorded in relicensecheck.pl
1 job for !3 with work/relicense in 13 minutes and 44 seconds (queued for 5 minutes and 35 seconds)
detached
Status Job ID Name Coverage
  Build
passed #66721
linux kf5-qt5 qt5.12

00:13:44

45.0%