Add test 1906: NCHAR/NVCHAR semantics on multi byte data.
Covers character based length, subscripts and truncation, locale aware case folding, and the NVARCHAR cases fixed in r13024. Skips itself if the machine has no UTF-8 locale.
Authored by: mikeaubury 2026-08-31
Parent: [r13024]
Child: [r13026]