Merge topic 'gitlab-ci-xcode-testing' into release-3.18

0f4777ab81 ci: don't test BundleGeneratorTest
77b44ed4ba gitlab-ci: add an Xcode tester
d33b38d4aa gitlab-ci: rename some scripts to be Linux-specific

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !4883