Create a new set of bindings to use for serializing the work graph nodes to the instant execution cache. Also allow a codec to create a nested context with a new isolate and codec to use for serializing nested objects. Use this to maintain a single isolate for all work nodes with nested isolates for each task instance.
Split out the code that uses a set of bindings to serialize to/from the instant execution cache from the code that builds the bindings. This allows the code that uses the bindings to be reused in a context where a different set of bindings is required, specifically when serializing transform nodes.