in TEST.groups we have
tier3 = \
    :build \
    :jdk_vector \
    :jdk_rmi \
    :jdk_beans \ <===
    :jdk_imageio \ <===
    :jdk_sound \ <===
    :jdk_client_sanity \ <===
    :jdk_jfr_tier3

The ones indicated with <==== were added to ensure we had some regular testing of the client headless jtreg tests in these test groups.

These are all also included in a jdk_deskgtop group but that group was not run regularly because too many of the other tests were not stable.

That has long since been resolved and we can delete the tier3 duplicates