Fixed a memory leak in v8 and another one in d8.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index c8d9c3a4f6ce573c7f67ffa2c2dce20513841e0f..cb63b2b3bf16808a0e28d63c6cd2670c207456c6 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1548,6 +1548,14 @@ Isolate::ThreadDataTable::ThreadDataTable()
 }
 
 
+Isolate::ThreadDataTable::~ThreadDataTable() {
+  // TODO(svenpanne) The assertion below would fire if an embedder does not
+  // cleanly dispose all Isolates before disposing v8, so we are conservative
+  // and leave it out for now.
+  // ASSERT_EQ(NULL, list_);
+}
+
+
 Isolate::PerIsolateThreadData*
     Isolate::ThreadDataTable::Lookup(Isolate* isolate,
                                      ThreadId thread_id) {
@@ -1735,6 +1743,11 @@ void Isolate::TearDown() {
 }
 
 
+void Isolate::GlobalTearDown() {
+  delete thread_data_table_;
+}
+
+
 void Isolate::Deinit() {
   if (state_ == INITIALIZED) {
     TRACE_ISOLATE(deinit);