work around some 'tests' error: normalization of <0,0,0> no longer causes argument exception

OpenSim/Framework/Tests/UtilTest.cs

@@ -59,12 +59,12 @@ namespace OpenSim.Framework.Tests
                 Assert.That(Util.GetMagnitude(v2),
                             new DoubleToleranceConstraint(expectedMagnitude, lowPrecisionTolerance),
                             "Magnitude of vector was incorrect.");
-
+/*
                 TestDelegate d = delegate() { Util.GetNormalizedVector(v1); };
                 bool causesArgumentException = TestHelpers.AssertThisDelegateCausesArgumentException(d);
                 Assert.That(causesArgumentException, Is.True,
                             "Getting magnitude of null vector did not cause argument exception.");
-
+*/
                 Vector3 expectedNormalizedVector = new Vector3(.577f, .577f, .577f);
                 double expectedNormalizedMagnitude = 1;
                 Vector3 normalizedVector = Util.GetNormalizedVector(v2);