Signed-off-by: Miguel Pires <[email protected]>

Adds a Checker to test that two containers have the same elements (duplicates must occur in the same number) but possibly in different orders.

Only top-level containers were matched in an unsorted way and maps
were compared with reflect.DeepEqual. Now map values are also "unsorted
matched" so values like map[string][]string can be compared regardless
of order even with nesting. Note that containers nested in slices or
arrays are still compared in the normal way.

Signed-off-by: Miguel Pires <[email protected]>
(cherry picked from commit 1af63c24476cb0a7409d499a76c8b5a59c04ca9c)

As suggested by staticcheck.io

(cherry picked from commit 4eff3617d9d1152874db2a2f8b6d90678f59c6b1)