named may terminate unexpectedly when processing ECS options in repeated responses to iterative queries

Processing of repeated responses to the same query, where both responses contain ECS pseudo-options, but where the first is broken in some way, can cause BIND to exit with an assertion failure.

'Broken' in this context is anything that would cause the resolver to reject the query response, such as a mismatch between query and answer name. This issue affects BIND 9 versions 9.11.4-S1 through 9.11.37-S1 and 9.16.8-S1 through 9.16.36-S1.