message: Delete test that depends on the relative timing of two things,
  which appears to make it sensitive to the load on the machine
  it is running on, and therefore quite flaky.
diff: @@ -20,7 +20,6 @@ from __future__ import print_function
  import functools
  import operator
  -import time
  import numpy as np
  @@ -121,29 +120,6 @@ class VariablesTestCase(test.TestCase):
  "test", cyclic)
  self.assertIs(initial_value, cyclic)
  - @test_util.run_deprecated_v1
  - def testCycleDetectionIsLinear(self):
  - # https://github.com/tensorflow/tensorflow/issues/28685
  -
  - def _build_tensor(depth):
  - fibonacci = [array_ops.zeros(shape=()), array_ops.ones(shape=())]
  - for _ in range(depth):
  - fibonacci.append(fibonacci[-2] + fibonacci[-1])
  - return fibonacci[-1]
  -
  - measurements = []
  - with self.cached_session():
  - for depth in range(15, 25):
  - with ops.Graph().as_default():
  - tensor = _build_tensor(depth)
  -
  - start_time = time.time()
  - variables._has_cycle(tensor.op, {})
  - end_time = time.time()
  - measurements.append(end_time - start_time)
  -
  - self.assertLess(max(measurements) / min(measurements), 10)
  -
  def testIterable(self):
  with self.assertRaisesRegexp(TypeError, "not iterable"):
  for _ in variables.Variable(0.0):
  