Remove vestigial file.

test/builders/user_builder.ex

-defmodule Pleroma.Builders.UserBuilder do
-  alias Pleroma.{User, Repo}
-
-  def build do
-   %User{
-      email: "test@example.org",
-      name: "Test Name",
-      nickname: "testname",
-      password_hash: Comeonin.Pbkdf2.hashpwsalt("test"),
-      bio: "A tester.",
-    }
-  end
-
-  def insert do
-    Repo.insert(build())
-  end
-end