Add more character overrides to two Latin locales.

[jmcwilliams403]

Firstly, removal of serif variants for specifically the Latin version of Capital/small Schwa unless under a supported Turkic locale, namely Azerbaijani whose usage of schwa comes directly from formerly using the Cyrillic script. This also incidentally returns it to its behavior from before engineering serif variants onto it (the serifs of the Cyrillic version are unchanged)

Secondly, removal of crossbar variants for Latin Z/z when under a Polish locale because, much like the reason Greek Zeta doesn't use crossbars, it makes it confusable with the handwritten form of another letter, which in this case is Ż/ż (whereas for Greek it's Ξ). Letters not used in Polish such as Ž/ž etc. are not affected.

Thirdly, make {super|sub|over|under}script forms of schwa, z, and i respond to localization overrides.