[NFC] Rename 'Ownership' to 'ReferenceOwnership'.

There's really two forms of ownership: references and values. Renaming
to make way for better distinguishing of the two.

stdlib/public/runtime/MetadataLookup.cpp

@@ -658,7 +658,7 @@ private:
   LookupDependentMemberFn lookupDependentMember;
 
   /// Ownership information related to the metadata we are trying to lookup.
-  TypeOwnership Ownership;
+  TypeReferenceOwnership ReferenceOwnership;
 
 public:
   DecodedMetadataBuilder(Demangler &demangler,
@@ -941,17 +941,17 @@ public:
   }
 
   BuiltType createUnownedStorageType(BuiltType base) {
-    Ownership.setUnowned();
+    ReferenceOwnership.setUnowned();
     return base;
   }
 
   BuiltType createUnmanagedStorageType(BuiltType base) {
-    Ownership.setUnmanaged();
+    ReferenceOwnership.setUnmanaged();
     return base;
   }
 
   BuiltType createWeakStorageType(BuiltType base) {
-    Ownership.setWeak();
+    ReferenceOwnership.setWeak();
     return base;
   }
 
@@ -960,7 +960,9 @@ public:
     return BuiltType();
   }
 
-  TypeOwnership getOwnership() const { return Ownership; }
+  TypeReferenceOwnership getReferenceOwnership() const {
+    return ReferenceOwnership;
+  }
 };
 
 }
@@ -1021,7 +1023,7 @@ swift::_getTypeByMangledName(StringRef typeName,
     });
 
   auto type = Demangle::decodeMangledType(builder, node);
-  return {type, builder.getOwnership()};
+  return {type, builder.getReferenceOwnership()};
 }
 
 SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL