CpuProfile: rename HSourcePosition to SourcePosition and move it to compiler.*

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 37020da1559b70828dfceedf5eb75cb32391817b..1b0907b293500868bddafbfb061676a602cc1333 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1906,6 +1906,9 @@ Isolate::~Isolate() {
   delete handle_scope_implementer_;
   handle_scope_implementer_ = NULL;
 
+  delete code_tracer();
+  set_code_tracer(NULL);
+
   delete compilation_cache_;
   compilation_cache_ = NULL;
   delete bootstrapper_;