Fix CPU profiler crash in start / stop sequence when non-existent name is passed

src/profile-generator-inl.h

Index: src/profile-generator-inl.h
diff --git a/src/profile-generator-inl.h b/src/profile-generator-inl.h
index fecb70b7753347686ed35ab86ef71e9a571db4a6..0c50581ab795ef2c3793a98f9c3b2c3324461a09 100644
--- a/src/profile-generator-inl.h
+++ b/src/profile-generator-inl.h
@@ -97,13 +97,6 @@ void CodeMap::DeleteCode(Address addr) {
 }
 
 
-bool CpuProfilesCollection::is_last_profile() {
-  // Called from VM thread, and only it can mutate the list,
-  // so no locking is needed here.
-  return current_profiles_.length() == 1;
-}
-
-
 const char* CpuProfilesCollection::GetFunctionName(String* name) {
   return GetFunctionName(GetName(name));
 }