message: Add per program op profile.
diff: @@ -8,6 +8,8 @@ message Profile {
  Node by_category = 1;
  // Root of a profile broken down by program structure.
  Node by_program_structure = 2;
  + // Per program profile, indexed by hlo module name of the program.
  + map<string, Node> per_program = 3;
  }
  // An entry in the profile tree. (An instruction, or set of instructions).
  