translate: do not clamp element index in generic_run

The buffer max_index value in translate_generic struct is relevant for indexed draw only. So do not clamp the element index in generic_run() as it is called for non-indexed draw only. This patch passes index_size to the common generic_run_one function so index clamping is only performed when a non-zero index_size is specified.

This fixes a text selection bug with kitty terminal emulator running on ARM when it falls back to the generic translate path for unsigned byte vertex array.

Reviewed-by: Jose Fonseca jfonseca@vmware.com