message: Only import tkinter when needed
  * Otherwise this could fail if tkinter isn't available on platforms where we're
  not even going to run the test
diff: import renderdoc as rd
  import rdtest
  import os
  -import tkinter
  class D3D12_RGP_Capture(rdtest.TestCase):
  @@ -19,6 +18,8 @@ class D3D12_RGP_Capture(rdtest.TestCase):
  rdtest.log.print("RGP capture not tested")
  return
  + import tkinter
  +
  # On D3D12 we need to create a real window
  window = tkinter.Tk()
  window.geometry("1280x720")
  