Memory read records are sometimes ignored by dynamic-dataflow

[bmitchell-lts]

If a memory read record is processed during an instruction, its contents are only consider if there is no known value already in the last modified table. This is true even if the value in the memory read record disputes the current value in the last modified table.

The analysis should process memory read records, compare them to the value in the last modified table, and issue a pseudo-operation if their values do not match. However, at the moment this is too expensive to do based on the current data structures used in the last modified table.

This issue will be fixed after a rewrite of the last modified table and value data structures.