Fix test_mult_norm_call_types on 32-bit systems

In that case, the default int is also 32-bit, so the test will fail to
be equal to `int64`. So instead of the implicit type, use an explicit
one.

Author: QuLogic

lib/matplotlib/tests/test_colors.py

@@ -1981,7 +1981,7 @@ def test_mult_norm_call_types():
     mn.vmin = (-2, -2)
     mn.vmax = (2, 2)
 
-    vals = np.arange(6).reshape((3,2))
+    vals = np.arange(6, dtype='int64').reshape((3, 2))
     target = np.ma.array([(0.5, 0.75),
                           (1., 1.25),
                           (1.5, 1.75)])