gitlab-ci: use separate output directories for {non-,}golioth tests

[mniestroj]

Since there were two invocations of twister in a row, first twister-out directory was renamed during second invocation. Additionally reports/ directory contents from first run got overwritten with contents from second run. This means that artifacts from first run were never accessible.

Run twister with --no-clean option, so that single twister-out directory is used. Test sets from both runs are unique, which means that the result will be a merged directory structure containing artifacts from both runs.

Use separate reports/ directory, so that reports from both runs are uploaded and available to be investigated.

[github-actions[bot]]

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