[ASDisplayNode] Ensure all subclasses are using base class __instanceLock__ and not re-defining their own. (#2754)

* [ASDisplayNode] Ensure all subclasses are using base class __instanceLock__ and not re-defining their own.

This also moves the @package definition of the instance variable to +FrameworkPrivate instead of Internal.h,
because Internal.h should ideally not be used outside of the ASDisplayNode file setup.  This has greatly reduced
the number of imports of Internal.h.

* [ASDisplayNode] Add ASDisplayNode+FrameworkSubclasses.h to share __instanceLock__ definition.

AsyncDisplayKit/ASImageNode.mm

@@ -15,22 +15,22 @@
 #import "_ASDisplayLayer.h"
 #import "ASAssert.h"
 #import "ASDimension.h"
-#import "ASDisplayNode+Subclasses.h"
-#import "ASDisplayNodeInternal.h"
+#import "ASDisplayNode+FrameworkSubclasses.h"
 #import "ASDisplayNodeExtras.h"
 #import "ASDisplayNode+Beta.h"
 #import "ASLayout.h"
 #import "ASTextNode.h"
 #import "ASImageNode+AnimatedImagePrivate.h"
-
 #import "ASImageNode+CGExtras.h"
 #import "AsyncDisplayKit+Debug.h"
-
 #import "ASInternalHelpers.h"
 #import "ASEqualityHelpers.h"
 #import "ASEqualityHashHelpers.h"
 #import "ASWeakMap.h"
 
+// TODO: It would be nice to remove this dependency; it's the only subclass using more than +FrameworkSubclasses.h
+#import "ASDisplayNodeInternal.h"
+
 #include <functional>
 
 struct ASImageNodeDrawParameters {
@@ -244,7 +244,7 @@ struct ASImageNodeDrawParameters {
   _drawParameter = {
     .bounds = self.bounds,
     .opaque = self.opaque,
-    .contentsScale = _contentsScaleForDisplay,
+    .contentsScale = self.contentsScaleForDisplay,
     .backgroundColor = self.backgroundColor,
     .contentMode = self.contentMode,
     .cropEnabled = _cropEnabled,