menu_cbs_sublabel: convert the uniform dispatch cases to a searched table

Eight hundred five groups of the thousand-case sublabel switch -
826 labels, each case a bind and a break - become one const table
of label and callback rows, platform guards carried inside; the 232
cases with surrounding guard scope or extra logic stay in the
residual switch, and groups whose guards span group boundaries were
left literal rather than lose their scope. Lookup is a linear scan
of the const table, keeping every row in read-only, link-resolved
storage on non-PIE targets rather than paying a runtime sort with
dirty pages.

Verified by a transient in-binary referee holding the original
switch: all 6,403 enums bind identical pointers through the new
path, zero mismatches, run against this exact form. The file drops
1,565 lines - 6,073 to 4,508 - and the object 18.5 kilobytes,
12.4 of text and a net 6 of data, the switch's jump tables having
cost more than the table that replaced them.

Author: libretroadmin