Clang importer: move name translation for throwing methods into importFullName.

The translation from the Objective-C NSError** convention into Swift
throwing methods alters the names of methods. Move that computation
into importFullName. This should be NFC refactoring for everything
except the Swift name lookup tables, which will now correctly reflect
this name translation.

Author: DougGregor

include/swift/AST/Identifier.h

@@ -438,34 +438,6 @@ class ObjCSelector {
   /// \param scratch Scratch space to use.
   StringRef getString(llvm::SmallVectorImpl<char> &scratch) const;
 
-  /// Ask whether this selector is a nullary selector (taking no
-  /// arguments) whose name matches the given piece.
-  bool isNullarySelector(StringRef piece) const {
-    if (Storage.isSimpleName()) {
-      return Storage.getBaseName().str() == piece;
-    } else {
-      return false;
-    }
-  }
-
-  /// Ask whether this selector is a non-nullary selector matching the
-  /// given literal pieces.
-  bool isNonNullarySelector(ArrayRef<StringRef> pieces) const {
-    if (Storage.isSimpleName()) {
-      return false;
-    }
-
-    ArrayRef<Identifier> args = Storage.getArgumentNames();
-    if (args.size() != pieces.size())
-      return false;
-
-    for (size_t i = 0, e = args.size(); i != e; ++i) {
-      if (args[i].str() != pieces[i])
-        return false;
-    }
-    return true;
-  }
-
   void *getOpaqueValue() const { return Storage.getOpaqueValue(); }
   static ObjCSelector getFromOpaqueValue(void *p) {
     return ObjCSelector(DeclName::getFromOpaqueValue(p));