Allow and process DataFetcherResult as an item for GraphQL List fields.

fixes graphql-java#1524 (graphql-java#1525)

* fixes graphql-java#1524

* fixes graphql-java#1524

This fixes up the example code so it used CodeRegistry and also quick…

… rename of parameter names there

Merge pull request graphql-java#1445 from tsroka/visit-fragments

Add support for visiting fragment definitions in QueryVisitor.

Merge pull request graphql-java#1450 from tinnou/9.x-fix-classCastExc…

…eption-type-condition-input-type

Fix graphql-java#1440 ClassCastException when using a fragment with wrong input type condition and overlapping fields are being merged.

Merge pull request graphql-java#1450 from tinnou/9.x-fix-classCastExc…

…eption-type-condition-input-type

Fix graphql-java#1440 ClassCastException when using a fragment with wrong input type condition and overlapping fields are being merged.

add test to show that BatchedExecutionStrategy doesn't work

across different paths

Alternative fix to dead lock challenge (graphql-java#1255)

* Added @OverRide as part of errorprone code health check

* Revert "Added @OverRide as part of errorprone code health check"

This reverts commit 38dfab1

* Brads attempt at graphql-java#1234

* Missed the test

fix master deployment

backport of graphql-java#1182