This allows us to map back from a type to the declaration in the dump,
so that we can perform more fine-grained analysis like whether a string
has been changed to string enum.
The tool should diagnose the change of extension's applicability since
such change can be source-breaking. We need first to support the
requirements in the module dump. Currently, we decorate each
member defined in extension with a field called extension info. The
field will keep track of the generic requirements that need to be satisfied
for this decorated member to be applicable. This patch doesn't implement the checking
of requirements change.
* 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.
