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

src/platform-openbsd.cc

Index: src/platform-openbsd.cc
diff --git a/src/platform-openbsd.cc b/src/platform-openbsd.cc
index 2b2d5308eb1cbceb8cd42f13999dae02dece5688..ba33a8444e23760a2b47585cb82e5c750074a8fd 100644
--- a/src/platform-openbsd.cc
+++ b/src/platform-openbsd.cc
@@ -793,11 +793,8 @@ class SignalSender : public Thread {
         vm_tgid_(getpid()),
         interval_(interval) {}
 
-  static void SetUp() {
-    if (!mutex_) {
-      mutex_ = OS::CreateMutex();
-    }
-  }
+  static void SetUp() { if (!mutex_) mutex_ = OS::CreateMutex(); }
+  static void TearDown() { delete mutex_; }
 
   static void InstallSignalHandler() {
     struct sigaction sa;
@@ -948,6 +945,12 @@ void OS::SetUp() {
 }
 
 
+void OS::TearDown() {
+  SignalSender::TearDown();
+  delete limit_mutex;
+}
+
+
 Sampler::Sampler(Isolate* isolate, int interval)
     : isolate_(isolate),
       interval_(interval),