[6.36] [core] Add a test for TColorGradient and disable failing tests on mac beta#21454

dpiparo merged 3 commits intoroot-project:v6-36-00-patchesroot-project/root:v6-36-00-patchesfrom

root-project-bot:BP_6.36_pull_21361root-project-bot/root:BP_6.36_pull_21361Copy head branch name to clipboard