message: updated tests to use ek.scoped_set_flag
diff: @@ -21,7 +21,10 @@ def test01_kernel_history(m):
  # Kernel history should be disabled by default
  assert len(ek.kernel_history()) == 0
  - ek.set_flag(ek.JitFlag.KernelHistory, True)
  + assert not ek.flag(ek.JitFlag.KernelHistory)
  +
  + with ek.scoped_set_flag(ek.JitFlag.KernelHistory, True):
  + assert ek.flag(ek.JitFlag.KernelHistory)
  for i in range(4):
  ek.eval(ek.arange(m.Float, i + 4))
  @@ -30,12 +33,13 @@ def test01_kernel_history(m):
  for i in range(4):
  assert history[i]['size'] == i + 4
  - ek.set_flag(ek.JitFlag.KernelHistory, False)
  + assert not ek.flag(ek.JitFlag.KernelHistory)
  # Kernel history should be erased after queried
  assert len(ek.kernel_history()) == 0
  +
  # TODO:
  # - Check number of kernel launched when scheduling variables to make sure it create a single kernel
  # - Check that number of output only contains the ones required (optimization)
  