Remove infrastructure for experimental JS natives

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 7c4e0a4735136257fde5c2708b4d036056d5d2de..fea4c0f039499384763d2def3ab739b19d1b7135 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -2785,9 +2785,6 @@ void Heap::CreateInitialObjects() {
   set_natives_source_cache(
       *factory->NewFixedArray(Natives::GetBuiltinsCount()));
 
-  set_experimental_natives_source_cache(
-      *factory->NewFixedArray(ExperimentalNatives::GetBuiltinsCount()));
-
   set_extra_natives_source_cache(
       *factory->NewFixedArray(ExtraNatives::GetBuiltinsCount()));