message: Adjust assert_negative/positive/non_negative/positive
  as they are unary assertion
diff: @@ -485,7 +485,8 @@ def assert_negative(x, data=None, summarize=None, message=None, name=None): # p
  'Condition x < 0 did not hold element-wise:',
  'x (%s) = ' % name, x]
  zero = ops.convert_to_tensor(0, dtype=x.dtype)
  - return assert_less(x, zero, data=data, summarize=summarize)
  + return _binary_assert('<', 'assert_less', math_ops.less, np.less, x, zero, data,
  + summarize, message=None, name=None, allow_empty=True)
  @tf_export('debugging.assert_positive', v1=[])
  @@ -536,7 +537,8 @@ def assert_positive(x, data=None, summarize=None, message=None, name=None): # p
  message, 'Condition x > 0 did not hold element-wise:',
  'x (%s) = ' % name, x]
  zero = ops.convert_to_tensor(0, dtype=x.dtype)
  - return assert_less(zero, x, data=data, summarize=summarize)
  + return _binary_assert('<', 'assert_less', math_ops.less, np.less, zero, x, data,
  + summarize, message=None, name=None, allow_empty=True)
  @tf_export('debugging.assert_non_negative', v1=[])
  @@ -590,7 +592,8 @@ def assert_non_negative(x, data=None, summarize=None, message=None, name=None):
  'Condition x >= 0 did not hold element-wise:',
  'x (%s) = ' % name, x]
  zero = ops.convert_to_tensor(0, dtype=x.dtype)
  - return assert_less_equal(zero, x, data=data, summarize=summarize)
  + return _binary_assert('<=', 'assert_less_equal', math_ops.less_equal,
  + np.less_equal, zero, x, data, summarize, message=None, name=None, allow_empty=True)
  @tf_export('debugging.assert_non_positive', v1=[])
  @@ -644,7 +647,8 @@ def assert_non_positive(x, data=None, summarize=None, message=None, name=None):
  'Condition x <= 0 did not hold element-wise:'
  'x (%s) = ' % name, x]
  zero = ops.convert_to_tensor(0, dtype=x.dtype)
  - return assert_less_equal(x, zero, data=data, summarize=summarize)
  + return _binary_assert('<=', 'assert_less_equal', math_ops.less_equal,
  + np.less_equal, x, zero, data, summarize, message=None, name=None, allow_empty=True)
  @tf_export('debugging.assert_equal', 'assert_equal', v1=[])
  