[ASTextNode] Go Back to Having Renderer as Ivar (#2376)

* Revert "Disable ASTextKitRenderer cache (#2315)"

This reverts commit 4aa7c9631d.

* Revert "[ASTextNode] Add NSCache based cache for ASTextKitRenderer (#2199)"

AsyncDisplayKit/TextKit/ASTextKitRenderer.mm

@@ -116,6 +116,31 @@ static NSCharacterSet *_defaultAvoidTruncationCharacterSet()
   return _calculatedSize;
 }
 
+- (void)setConstrainedSize:(CGSize)constrainedSize
+{
+  if (!CGSizeEqualToSize(constrainedSize, _constrainedSize)) {
+    _sizeIsCalculated = NO;
+    _constrainedSize = constrainedSize;
+    _calculatedSize = CGSizeZero;
+    
+    // Throw away the all subcomponents to create them with the new constrained size new as well as let the
+    // truncater do it's job again for the new constrained size. This is necessary as after a truncation did happen
+    // the context would use the truncated string and not the original string to truncate based on the new
+    // constrained size
+    __block ASTextKitContext *ctx = _context;
+    __block ASTextKitTailTruncater *tru = _truncater;
+    __block ASTextKitFontSizeAdjuster *adj = _fontSizeAdjuster;
+    _context = nil;
+    _truncater = nil;
+    _fontSizeAdjuster = nil;
+    ASPerformBlockOnDeallocationQueue(^{
+      ctx = nil;
+      tru = nil;
+      adj = nil;
+    });
+  }
+}
+
 - (void)_calculateSize
 {
   // if we have no scale factors or an unconstrained width, there is no reason to try to adjust the font size