swift234

[ClangImporter] Import known property accessors with consistent types.

Previously, the getter and setter for a property could disagree on what the
"type of the property" was: Unmanaged<CFType> vs. CFType, or COpaquePointer
vs. CMutableVoidPointer. Now, we treat property accessors as distinct from
normal methods when importing their parameter and result types, and have
those types follow the same rules as they would for the property itself.

This will need a bit of cleanup work once we're importing implicit properties
everywhere, but this handles the crashes and unfortunate limitations we were
seeing for WWDC.

<rdar://problem/16544938>

Swift SVN r17987