Add extreme_assertion check for edges in ProcessEdges

[k-sareen]

This adds an assertion which checks that edges we get inProcessEdgesWork are where we expect them to be. It is guarded by extreme_assertions. The assertion check is simple: it takes the trace_object() checks for each plan and converts them into an assertion when a new ProcessEdgesWork packet (for that plan) is created.

[k-sareen]

Related issue: #442

[k-sareen]

Very bit rotted and not useful PR anymore.