Remove all uses of field-tracking flags that do not make decisions but are subject to existing info…

src/json-parser.h

Index: src/json-parser.h
diff --git a/src/json-parser.h b/src/json-parser.h
index 72c69100d1651baaa893257e0ace9ef43b1624b8..c164ebfbf6b8e12ce6d5a8fec8febc215b4ded13 100644
--- a/src/json-parser.h
+++ b/src/json-parser.h
@@ -414,9 +414,7 @@ Handle<Object> JsonParser<seq_ascii>::ParseJsonObject() {
           if (value->FitsRepresentation(expected_representation)) {
             // If the target representation is double and the value is already
             // double, use the existing box.
-            if (FLAG_track_double_fields &&
-                value->IsSmi() &&
-                expected_representation.IsDouble()) {
+            if (value->IsSmi() && expected_representation.IsDouble()) {
               value = factory()->NewHeapNumber(
                   Handle<Smi>::cast(value)->value());
             }