Enable Conditional Numerical Reproducibility for tests

Author: sharwell

test/Microsoft.ML.TestFramework/GlobalBase.cs

@@ -25,6 +25,10 @@ public static void AssemblyInit()
             var prev = Contracts.SetAssertHandler(AssertHandler);
             Contracts.Check(prev == null, "Expected to replace null assertion handler!");
 
+            // Enable Conditional Numerical Reproducibility
+            // https://software.intel.com/en-us/articles/introduction-to-the-conditional-numerical-reproducibility-cnr
+            Environment.SetEnvironmentVariable("MKL_CBWR", "COMPATIBLE");
+
             // HACK: ensure MklImports is loaded very early in the tests so it doesn't deadlock while loading it later.
             // See https://github.com/dotnet/machinelearning/issues/1073
             Mkl.PptrfInternal(Mkl.Layout.RowMajor, Mkl.UpLo.Up, 0, Array.Empty<double>());