det: no end-to-end test of the batch Sysout writing bytes above X'7F' (#4691 follow-up) #4697

PR #4696 made the batch Sysout (batch forge _RUNTIME) encode in the record charset. The e2e byte test covers the standalone Sysout only; _java_run_batch decodes stdout as text. Add a batch-path DISPLAY of X'80'..X'FF' vs cobc (raw bytes), including a non-latin-1 data_encoding case. Part of #4270.