Age inline caches after context disposal.

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index 672b490ff479ea8e09e0293aef56694d9a3c34c2..8c37c99fe461b02d44a677c578ea10db045a0f17 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -1065,7 +1065,17 @@ class Heap {
   void EnsureHeapIsIterable();
 
   // Notify the heap that a context has been disposed.
-  int NotifyContextDisposed() { return ++contexts_disposed_; }
+  int NotifyContextDisposed() {
+    return ++contexts_disposed_;
+  }
+
+  void NotifyGlobalContextDisposed() {
+    ++global_context_disposed_count_;
+  }
+
+  int global_context_disposed_count() {
+    return global_context_disposed_count_;
+  }
 
   // Utility to invoke the scavenger. This is needed in test code to
   // ensure correct callback for weak global handles.
@@ -1612,6 +1622,8 @@ class Heap {
   // For keeping track of context disposals.
   int contexts_disposed_;
 
+  int global_context_disposed_count_;
+
   int scan_on_scavenge_pages_;
 
 #if defined(V8_TARGET_ARCH_X64)