Pack some of the arrays that contain locale data more tightly. The
AlphaCode struct is a char[4] but always holds only [a-z]{,3} which
could be fit into 16 bits, halving the size of an AlphaCode struct.
With the new constructor the initialization of the AlphaCode struct
also changes - modify qlocalexml2cpp.py to reflect this change and
regenerate the languageCodeList.
Fixes: QTBUG-105050
Change-Id: I2b1e93ab7cc3f2d667bf67b45769b74a15211931
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>