IcuCollation::$tailoringFirstLetters: 'en', 'it', 'hu', 'pt', 'uk' verified

* en: obviously
* it: per Nemo_bis in comments on change I97273c52
* hu: per Tisza Gergő in comments on bug 45596
* pt: 'uca-default' collation is deployed on pt.wiki, 'uca-pt' is the same thing
* uk: per Dmytro Dziuma in comments on bug 45444

Change-Id: Ia7568a9ad40ef991b73059b5269e6236f52681f1