Bug 18336: Full stack tests for supplemental UTF-8 chars

Bug 18336: Full stack tests for supplemental UTF-8 chars

This patch introduces tests for Koha's support for 4-byte supplemental
UTF-8 chars. encoding/decoding tools handle this gracefuly. The missing
piece is the MySQL DB backend.

The tests in this patch:
- Adds a couple records for each flavour (MARC21 and UNIMARC) so
  search_utf8.t tests 4-byte chars are handled correctly
- Adds emoji testing in auth_values_input_www.t

To test:
- Apply this patch
- Run:
  $ kshell
 k$ prove t/db_dependent/www/search_utf8.t \
          t/db_dependent/www/auth_values_input_www.t
=> FAIL: It should fail if the DB hasn't been migrated into using
utf8mb4

Sponsored-by: Hotchkiss School
Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>