Issue 28027. Move Null to the bottom in the Analyzer.

pkg/analyzer/lib/src/task/strong_mode.dart

Index: pkg/analyzer/lib/src/task/strong_mode.dart
diff --git a/pkg/analyzer/lib/src/task/strong_mode.dart b/pkg/analyzer/lib/src/task/strong_mode.dart
index c5b6badf091a85d6a21c4cf309817c6559bac1b6..866d17bc9bb041d7142c84b676a6257f2de4cab6 100644
--- a/pkg/analyzer/lib/src/task/strong_mode.dart
+++ b/pkg/analyzer/lib/src/task/strong_mode.dart
@@ -368,7 +368,7 @@ class InstanceMemberInferrer {
           newType = fieldElement.initializer.returnType;
         }
       }
-      if (newType == null || newType.isBottom) {
+      if (newType == null || newType.isBottom || newType.isDartCoreNull) {
         newType = typeProvider.dynamicType;
       }
       setFieldType(fieldElement, newType);