[api] Introduce fast instantiations cache

src/heap/object-stats.cc

Index: src/heap/object-stats.cc
diff --git a/src/heap/object-stats.cc b/src/heap/object-stats.cc
index e30d84950e007318a82dcace7fe74392ad2114f0..743c46411b43f9353ea20988b88c15ef409150e9 100644
--- a/src/heap/object-stats.cc
+++ b/src/heap/object-stats.cc
@@ -465,8 +465,13 @@ void ObjectStatsCollector::RecordFixedArrayDetails(FixedArray* array) {
   }
   if (array->IsNativeContext()) {
     Context* native_ctx = Context::cast(array);
-    RecordHashTableHelper(array, native_ctx->template_instantiations_cache(),
-                          TEMPLATE_INSTANTIATIONS_CACHE_SUB_TYPE);
+    RecordHashTableHelper(array,
+                          native_ctx->slow_template_instantiations_cache(),
+                          SLOW_TEMPLATE_INSTANTIATIONS_CACHE_SUB_TYPE);
+    FixedArray* fast_cache = native_ctx->fast_template_instantiations_cache();
+    stats_->RecordFixedArraySubTypeStats(
+        fast_cache, FAST_TEMPLATE_INSTANTIATIONS_CACHE_SUB_TYPE,
+        fast_cache->Size(), 0);
   }
 }