* swift-api-digester: ensure constructors are detected as removed if not moved. rdar://31694119
* swift-api-digester: types with the same printed name are considered behavior-preserving. rdar://31694085
* [test] Using tmp directory from build.
This structure serves multiple purposes:
a. Allow migrator to speak in the same language with swift-api-digester in terms of API changes.
b. Serialize/Deserialize detected API change items in JSON format.
c. Manage memory after deserializing API change items.
d. Facilitate look up by USRs of APIs under migration.
The structure is tested by round-trip serialization and deserialization.
* swift-api-digester: Add a test for generating migrator script.
* swift-api-digester: Add #ifndef guard before each macro category.
* swift-api-digester: Avoid printing macro categories with empty content.
* swift-api-digester: Add test for multiple type changes in a single decl.
* swift-api-digester: simplify some code. NFC
* swift-api-digester: consider name alias type as a standalone node kind.
* [test] Update the swift-api-digester dump for stdlib to honor new name alias node.
