swift234

Importer: Prefer more available convenience factory initializers over less available convenience initializers

Update the importer and name lookup to prefer a factory initializer that is more available
over a convenience initializer that is less available even though we generally prefer
convenience initializers over convenience factory initializers. The motivation for this
change is CIColor, which has added a new convenience initializer:

- (instancetype)initWithRed:(CGFloat)r green:(CGFloat)g blue:(CGFloat)b NS_AVAILABLE(10_11, 9_0);

but already has existing convenience factory initializer:

+ (instancetype)colorWithRed:(CGFloat)r green:(CGFloat)g blue:(CGFloat)b;

Without this change we prefer -initWithRed:green:blue, so instantiating CIColor with:

let colorChannelValue: CGFloat = …
let ciColor = CIColor(red: colorChannelValue, green: colorChannelValue, blue: colorChannelValue)

results in an availability error even though there is a perfectly available convenience
factory initializer. With this change, we choose the convenience factory initializer
when importing, so there is no availability error.

rdar://problem/20617581

Swift SVN r30946