Precompiled queries: calculate the NRT status of complex expressions in the funcletizer

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Our current SQL pregeneration mechanism (#29753) takes into account the nullability of reference type parameters; that is, if a reference type variable is captured by the query, and that variable is annotated as non-nullable, our SQL generation takes that into account, generating optimal SQL (and also reducing the number of required SQL permutations).

However, the funcletizer currently only does this for directly captured variables, and notfor larger expressions composed on top of a captured variable (e.g. Where(b => b.Name == foo + "Bla")). Doing this would require bubbling nullability information up the tree via State, and knowing to correctly know to combine operand nullabilities per expression type.