message: Fix the unspecified behavior when updating {left,right}_map for xla_einsum shape inference.
diff: @@ -562,11 +562,11 @@ REGISTER_OP("XlaEinsum")
  lhs_rhs_split[1], "'", " with size: ", lhs_rhs_split[1].size()));
  }
  - for (const char& c : lhs_rhs_split[0]) {
  - left_map[c] = context->Dim(input_a, left_map.size());
  + for (int i = 0; i < lhs_rhs_split[0].size(); ++i) {
  + left_map[lhs_rhs_split[0][i]] = context->Dim(input_a, i);
  }
  - for (const char& c : lhs_rhs_split[1]) {
  - right_map[c] = context->Dim(input_b, right_map.size());
  + for (int i = 0; i < lhs_rhs_split[1].size(); ++i) {
  + right_map[lhs_rhs_split[1][i]] = context->Dim(input_b, i);
  }
  for (const char& c : equation_split[1]) {
  