Remove checked mode references (#146845)

Fixes flutter/flutter#21066

Author: goderbauer

packages/flutter/lib/src/rendering/box.dart

@@ -1522,7 +1522,7 @@ abstract class RenderBox extends RenderObject {
     assert(RenderObject.debugCheckingIntrinsics || !debugDoingThisResize); // performResize should not depend on anything except the incoming constraints
     bool shouldCache = true;
     assert(() {
-      // we don't want the checked-mode intrinsic tests to affect
+      // we don't want the debug-mode intrinsic tests to affect
       // who gets marked dirty, etc.
       shouldCache = !RenderObject.debugCheckingIntrinsics;
       return true;

packages/flutter/lib/src/rendering/object.dart

@@ -2205,11 +2205,11 @@ abstract class RenderObject with DiagnosticableTreeMixin implements HitTestTarge
   }
   Constraints? _constraints;
 
-  /// Verify that the object's constraints are being met. Override
-  /// this function in a subclass to verify that your state matches
-  /// the constraints object. This function is only called in checked
-  /// mode and only when needsLayout is false. If the constraints are
-  /// not met, it should assert or throw an exception.
+  /// Verify that the object's constraints are being met. Override this function
+  /// in a subclass to verify that your state matches the constraints object.
+  /// This function is only called when asserts are enabled (i.e. in debug mode)
+  /// and only when needsLayout is false. If the constraints are not met, it
+  /// should assert or throw an exception.
   @protected
   void debugAssertDoesMeetConstraints();