[maglev] Display function name when showing graph

This make it easier to follow which function was compiled when many
maglev graphs are outputted.

Bug: v8:7700
Change-Id: If88f6d4aa7306df8a26601f081105bff0eb9c5e8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3616513
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80279}

src/maglev/maglev-compiler.cc

@@ -180,7 +180,12 @@ void MaglevCompiler::Compile(LocalIsolate* local_isolate,
   }
 
   if (FLAG_print_maglev_graph) {
-    std::cout << "After graph buiding" << std::endl;
+    MaglevCompilationUnit* top_level_unit =
+        compilation_info->toplevel_compilation_unit();
+    std::cout << "Compiling " << Brief(*top_level_unit->function().object())
+              << " with Maglev\n";
+    top_level_unit->bytecode().object()->Disassemble(std::cout);
+    std::cout << "\nAfter graph buiding" << std::endl;
     PrintGraph(std::cout, compilation_info, graph_builder.graph());
   }