static Map<String, Set<String>> getPdxClasstofieldsmap() {
    return pdxClassToFieldsMap.get();
  }
Caches the fields not found in any Pdx version. This threadlocal will be cleaned up after query
execution completes in {@linkplain #executeUsingContext(ExecutionContext)}
geode-core/src/main/java/org/apache/geode/cache/query/internal/DefaultQuery.java