Remove obsolete method ProfileTree::AddPathFromStart and the corresponding test.

src/profile-generator.h

Index: src/profile-generator.h
diff --git a/src/profile-generator.h b/src/profile-generator.h
index 17ec10b44d3ac9fd311e2786fda159893504132c..679e9298124f5d7e06cae14aac48d52cea38ddda 100644
--- a/src/profile-generator.h
+++ b/src/profile-generator.h
@@ -198,8 +198,6 @@ class ProfileTree {
   ProfileNode* AddPathFromEnd(
       const Vector<CodeEntry*>& path,
       int src_line = v8::CpuProfileNode::kNoLineNumberInfo);
-  void AddPathFromStart(const Vector<CodeEntry*>& path,
-                        int src_line = v8::CpuProfileNode::kNoLineNumberInfo);
   ProfileNode* root() const { return root_; }
   unsigned next_node_id() { return next_node_id_++; }