[Test] fix Image.fromarray LA mode test

AppVeyor: ERROR: Failure: ImportError (No module named numpy)

inspired from: Tests/test_numpy.py

Tests/test_image_fromarray_la.py

@@ -2,18 +2,28 @@ from helper import unittest, PillowTestCase
 
 from PIL import Image
 
-import numpy as np
+try:
+    import site
+    import numpy
+except ImportError:
+    # Skip via setUp()
+    pass
 
 class TestImageFromArrayLA(PillowTestCase):
 
-    def test_sanity(self):
-        ar1 = (np.random.random((40,40,2))*255).astype('uint8')
-        im1 = Image.fromarray(ar1)
-        arr = np.array(im1.getdata(), 'uint8')
-        ar2 = arr.reshape(im1.size[1], im1.size[0], arr.shape[1])
-        im2 = Image.fromarray(ar2)
+    def setUp(self):
+        try:
+            import site
+            import numpy
+        except ImportError:
+            self.skipTest("ImportError")
 
-        self.assert_image_equal(im1, im2)
+    def test_sanity(self):
+        ar1 = (numpy.random.random((40,40,2))*255).astype('uint8')
+        im1 = Image.fromarray(ar1)
+        arr = numpy.array(im1.getdata(), 'uint8')
+        ar2 = arr.reshape(im1.size[1], im1.size[0], arr.shape[1])
+        self.assertTrue(numpy.array_equal(ar1, ar2))
 
 
 if __name__ == '__main__':