In the typeof() optimization in OP_Column, expand the size of the bogus buffer

In the typeof() optimization in OP_Column, expand the size of the bogus buffer
provided for data so that it is big enough to cover the increased number of
bytes displayed during register tracing from check-in [54553bf16fabd72d].
This is the correct fix for ticket [bbd55a97e66ff50d], though the earlier one
does not hurt and is useful to retain.

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