Faster introspection

[gnawf]

trafficstars

Experimental change for faster introspection by avoiding some of the GraphQL Java execution overhead.

Old

    // Benchmark                                    Mode  Cnt    Score   Error  Units
    // IntrospectionBenchmarkJava.benchMarkAvgTime  avgt   20  134.819 ± 5.109  ms/op

New

    // Benchmark                                    Mode  Cnt   Score   Error  Units
    // IntrospectionBenchmarkJava.benchMarkAvgTime  avgt   20  30.656 ± 0.949  ms/op

If we like this approach I'll clean up the code and add an execution hint/feature flag.