archiver: Speed up tests

archiver: Speed up tests

When running tests locally without the advantage of a populated sstate
cache, the archiver tests can take an unnecessarily long time. Using
different target recipes can speed things up a lot by reducing the
number of dependencies that are built.

For the test case test_archiver_srpm_mode we can still test the
conditions described in bug #11121 by using a target recipe that is
known to inherit the nopackages class as well as a more normal recipe,
instead of having to compute all the depepndencies of core-image-sato.

Before:
    archiver.Archiver.test_archiver_allows_to_filter_on_recipe_name: PASSED (20.50s)
    archiver.Archiver.test_archiver_filters_by_type: PASSED (14.16s)
    archiver.Archiver.test_archiver_filters_by_type_and_name: PASSED (79.08s)
    archiver.Archiver.test_archiver_mode_configured: PASSED (558.19s)
    archiver.Archiver.test_archiver_mode_diff: PASSED (14.59s)
    archiver.Archiver.test_archiver_mode_dumpdata: PASSED (14.41s)
    archiver.Archiver.test_archiver_mode_mirror: PASSED (14.02s)
    archiver.Archiver.test_archiver_mode_mirror_combined: PASSED (19.99s)
    archiver.Archiver.test_archiver_mode_mirror_excludes: PASSED (14.24s)
    archiver.Archiver.test_archiver_mode_mirror_gitsm: PASSED (13.47s)
    archiver.Archiver.test_archiver_mode_mirror_gitsm_shallow: PASSED (22.15s)
    archiver.Archiver.test_archiver_mode_original: PASSED (14.15s)
    archiver.Archiver.test_archiver_mode_patched: PASSED (14.57s)
    archiver.Archiver.test_archiver_mode_recipe: PASSED (14.56s)
    archiver.Archiver.test_archiver_srpm_mode: PASSED (83.03s)
    oe-selftest () - Ran 15 tests in 911.905s

After:
    archiver.Archiver.test_archiver_allows_to_filter_on_recipe_name: PASSED (23.66s)
    archiver.Archiver.test_archiver_filters_by_type: PASSED (15.16s)
    archiver.Archiver.test_archiver_filters_by_type_and_name: PASSED (15.33s)
    archiver.Archiver.test_archiver_mode_configured: PASSED (15.94s)
    archiver.Archiver.test_archiver_mode_diff: PASSED (15.79s)
    archiver.Archiver.test_archiver_mode_dumpdata: PASSED (15.39s)
    archiver.Archiver.test_archiver_mode_mirror: PASSED (15.28s)
    archiver.Archiver.test_archiver_mode_mirror_combined: PASSED (21.22s)
    archiver.Archiver.test_archiver_mode_mirror_excludes: PASSED (15.11s)
    archiver.Archiver.test_archiver_mode_mirror_gitsm: PASSED (13.61s)
    archiver.Archiver.test_archiver_mode_mirror_gitsm_shallow: PASSED (23.21s)
    archiver.Archiver.test_archiver_mode_original: PASSED (14.87s)
    archiver.Archiver.test_archiver_mode_patched: PASSED (15.50s)
    archiver.Archiver.test_archiver_mode_recipe: PASSED (15.62s)
    archiver.Archiver.test_archiver_srpm_mode: PASSED (20.66s)
    oe-selftest () - Ran 15 tests in 257.170s

Signed-off-by: Paul Barker <pbarker@konsulko.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>