4.x: usage of ByteArrayInputStream.transferTo(OutputStream) may fail on Java 21.0.2

[tomas-langer]

In Java 21.0.2 a constant was introduced to limit the amount of bytes sent in a single write event, so the whole buffer is not sent at once.
Due to a bug in FixedBufferData, the offset was not calculated correctly and a few tests stopped working (where we use 1 Mbi of data, as the limit is 131_072 bytes).