The seldom used '--include-tags' and '--exclude-tags' flags allows a testing user to remove and include tags from the search used by TestLib to select tests. For example, by default the 'quick' tag is included as part of the search of tests to run. The '--exclude-tags' flag could then be used to remove the 'quick' tags from the search. The TestLib framework was applying the regex these flags input before the default flags. This meant if the user wished to remove a flag, it was impossible. This is now applied after. Change-Id: I569e0f8d6093ff5e5cdc76faff89c15e75ff297a Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/56830 Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Maintainer: Jason Lowe-Power <power.jg@gmail.com> Tested-by: kokoro <noreply+kokoro@google.com>