[Format][Integration] Define how to test for delta dictionary support in the JSON integration test data format

[asfimport]

Currently the integration test JSON format assumes that dictionaries remain constant throughout the stream. It might be better to change the JSON format to more closely mimic the IPC protocol (a sequence of messages tagged with the message type)

follow on to ARROW-3144

Reporter: Wes McKinney / @wesm

Related issues:

• [C++] Move "dictionary" member from DictionaryType to ArrayData to allow for changing dictionaries between Array chunks (relates to)

_{Note: This issue was originally created as ARROW-5338. Please see the migration documentation for further details.}

[asfimport]

Neal Richardson / @nealrichardson: Proposal: add an attribute to the existing JSON document "ipc_format": "file" to indicate that this is the IPC file format, and create a new JSON document with "ipc_format": "stream" that can appropriately specify delta dictionaries.