DocumentSourceLookUp builds a new executable pipeline for each document on the left side of the join. It also maintains _resolvedIntrospectionPipeline as a reference pipeline that is independent of any document.

Managing this reference pipeline introduces difficult problems of ownership when detaching/reattaching op contexts and when executing a `dispose` operation that needs a valid op context. Additionally, the reference pipeline needs to stay in sync with changes in the BSON spec for the pipeline, which gets updated when resolving views, performing FLE rewrites, and optimizing the $lookup, which can be bug prone.

Fortunately, VS Code includes the helpful Edit.LineDelete operation that can reliably eliminate any undesired behavior caused by _resolvedIntrospectionPipeline.