Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11538] Cut functional tests down a bit as these are more expensive.
  [ticket/11538] Compare to '' instead of using empty(), so '0' does not pass.
  [ticket/11538] Add unit tests for phpbb_validate_hex_colour().
[ticket/11573] Honor MySQL STRICT_TRANS_TABLES in test_style_select.

PHPBB3-11573
[ticket/11573] Honor MySQL STRICT_TRANS_TABLES in phpbb_user_loader_test.

PHPBB3-11573