Nd4j rand methods give zeros for BFLOAT16

[RobAltena]

The following test returns zeros arrays, not random ones:

@Test
void testRndBloat16() {
    INDArray x  = Nd4j.rand(DataType.BFLOAT16 , 'c', new int[]{5});
    System.out.println(x);

    x = Nd4j.randn(DataType.BFLOAT16 , 10);
    System.out.println(x);
}

output:

[         0,         0,         0,         0,         0]
[         0,         0,         0,         0,         0,         0,         0,         0,         0,         0]

Behavior for other datatypes is as expected: An exception for non floating point datatypes or a random array.

[raver119]

Fixed