Valgrind cleanliness, part 6: Introduce OS::TearDown, cleaning up 2 mutexes.

src/v8.cc

Index: src/v8.cc
diff --git a/src/v8.cc b/src/v8.cc
index 45036c83f5decc5028b8159ccbd6b1280c1aaeef..2910a0700d92223521dddf8a072fc65fb6fa9615 100644
--- a/src/v8.cc
+++ b/src/v8.cc
@@ -118,6 +118,8 @@ void V8::TearDown() {
 
   delete call_completed_callbacks_;
   call_completed_callbacks_ = NULL;
+
+  OS::TearDown();
 }
 
 
@@ -248,7 +250,6 @@ Object* V8::FillHeapNumberWithRandom(Object* heap_number,
 }
 
 void V8::InitializeOncePerProcessImpl() {
-  // Set up the platform OS support.
   OS::SetUp();
 
   use_crankshaft_ = FLAG_crankshaft;