HPCC-10040 Increase blockSize value to avoid "End of record not found..."
exception during XML spray

Rework after rewiev.
Increase maximum record size to 0x100000 (1MB).

Signed-off-by: Attila.Vamos <attila.vamos@gmail.com>
Signed-off-by: Attila Vamos <attila.vamos@gmail.com>