MatrixFactorizationSimpleTrainAndPredict() on MacOS is broken

[mstfbl]

The test MatrixFactorizationSimpleTrainAndPredict() is run on MacOS, but its calculate MSE is not checked. It is denoted as "broken" on MacOS.

machinelearning/test/Microsoft.ML.Tests/TrainerEstimators/MatrixFactorizationTests.cs

Lines 135 to 141 in fbd1b93

	else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
	{
	// The Mac case is just broken. Should be fixed later. Re-enable when done.
	// Mac case
	//var expectedMacL2Error = 0.61192207960271; // Mac baseline
	//Assert.InRange(metrices.L2, expectedMacL2Error - 5e-3, expectedMacL2Error + 5e-3); // 1e-7 is too small for Mac so we try 1e-5
	}