Get rid of promotedType=none annotations

pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart

Index: pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
diff --git a/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart b/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
index b96c845ae5197456ed7bd7fdfd113a040a7300bc..b4b6cfad15c09de3576979d2b06865d6f191a9b9 100644
--- a/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
+++ b/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
@@ -570,13 +570,10 @@ abstract class TypeInferrerImpl<S, E, V, F> extends TypeInferrer<S, E, V, F> {
       void setPromotedType(DartType type)) {
     DartType promotedType = typePromoter.computePromotedType(
         typePromotionFact, typePromotionScope, mutatedInClosure);
-    instrumentation?.record(
-        Uri.parse(uri),
-        offset,
-        'promotedType',
-        promotedType != null
-            ? new InstrumentationValueForType(promotedType)
-            : const InstrumentationValueLiteral('none'));
+    if (promotedType != null) {
+      instrumentation?.record(Uri.parse(uri), offset, 'promotedType',
+          new InstrumentationValueForType(promotedType));
+    }
     setPromotedType(promotedType);
     return typeNeeded ? (promotedType ?? declaredOrInferredType) : null;
   }