jnp.flip crashes when given a tuple of axes
Please:

- [x] Check for duplicate issues.
- [x] Provide a complete example of how to reproduce the bug, wrapped in triple backticks like this:

```python
import jax.numpy as jnp
jnp.flip(jnp.zeros((3, 3, 3)), axis=(1,2))
```

- [x] If applicable, include full error messages/tracebacks.
```
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/buehrle/dev/polyssimo/.venv/lib/python3.6/site-packages/jax/_src/numpy/lax_numpy.py", line 1114, in flip
    return lax.rev(m, [_canonicalize_axis(axis, ndim(m))])
  File "/home/buehrle/dev/polyssimo/.venv/lib/python3.6/site-packages/jax/_src/util.py", line 262, in canonicalize_axis
    axis = operator.index(axis)
TypeError: 'tuple' object cannot be interpreted as an integer
```
diff --git a/jax/_src/numpy/lax_numpy.py b/jax/_src/numpy/lax_numpy.py
index 582eb4f73..ae6533530 100644
--- a/jax/_src/numpy/lax_numpy.py
+++ b/jax/_src/numpy/lax_numpy.py
@@ -1111,7 +1111,8 @@ def flip(m, axis: Optional[Union[int, Tuple[int, ...]]] = None):
   _check_arraylike("flip", m)
   if axis is None:
     return lax.rev(m, list(range(len(shape(m)))))
-  return lax.rev(m, [_canonicalize_axis(axis, ndim(m))])
+  axis = _ensure_index_tuple(axis)
+  return lax.rev(m, [_canonicalize_axis(ax, ndim(m)) for ax in axis])
 
 
 @_wraps(np.fliplr)
diff --git a/tests/lax_numpy_test.py b/tests/lax_numpy_test.py
index 422719e3b..2b540114b 100644
--- a/tests/lax_numpy_test.py
+++ b/tests/lax_numpy_test.py
@@ -3449,7 +3449,7 @@ class LaxBackedNumpyTests(jtu.JaxTestCase):
        "shape": shape, "dtype": dtype, "axis": axis}
       for shape in [(3,), (2, 3)]
       for dtype in default_dtypes
-      for axis in list(range(-len(shape), len(shape))) + [None]  # Test negative axes
+      for axis in list(range(-len(shape), len(shape))) + [None] + [tuple(range(len(shape)))]  # Test negative axes and tuples
     ))
   def testFlip(self, shape, dtype, axis):
     rng = jtu.rand_default(self.rng())
['jax/_src/numpy/lax_numpy.py', 'tests/lax_numpy_test.py']