Helix Integration.

[michaelgsharp]

This PR changes the CI testing process to use Helix instead of testing on the build machines (except for the code coverage tests currently). This lets us take advantage of more powerful machines for our testing.

I disabled 6 tests tracked here #5845 due to slight differences between the results in the helix machines and the build machines.

This PR also fixes a bug in the MatrixFactorizationNative where we were compiling the native code to be compatible with Intel CPU's only.

[justinormont]

Description of helix: (I had look up helix)

Helix is the distributed test platform that we use to run tests. We build a helix payload that contains the publish directory of every test project that we want to test send a job with with this payload to a set of queues for the various combinations of OS that we want to test for example: Windows.10.Amd64.ClientRS4.VS2017.Open, OSX.1012.Amd64.Open, Ubuntu.1804.Amd64.Open. Helix takes care of unzipping, running the job, and reporting results.

via: https://github.com/dotnet/aspnetcore/blob/83f7970b8cf3d87299d564e713caa0310eaf326b/docs/Helix.md

[michaelgsharp]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[codecov]

Codecov Report

Merging #5837 (bc11aae) into main (6114b4f) will decrease coverage by 0.26%.
The diff coverage is 46.77%.

@@            Coverage Diff             @@
##             main    #5837      +/-   ##
==========================================
- Coverage   68.46%   68.20%   -0.27%     
==========================================
  Files        1134     1134              
  Lines      241911   241939      +28     
  Branches    25109    25298     +189     
==========================================
- Hits       165628   165018     -610     
- Misses      69785    70267     +482     
- Partials     6498     6654     +156     

Flag	Coverage Δ
Debug	68.20% <46.77%> (-0.27%)	⬇️
production	62.86% <0.00%> (-0.21%)	⬇️
test	88.82% <49.15%> (-0.49%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...icrosoft.ML.Core/Utilities/ResourceManagerUtils.cs	59.15% <0.00%> (-2.46%)	⬇️
.../Microsoft.ML.AutoML.Tests/ColumnInferenceTests.cs	96.29% <0.00%> (-2.44%)	⬇️
...r.Tests/ApprovalTests/ConsoleCodeGeneratorTests.cs	99.54% <0.00%> (-0.46%)	⬇️
....CodeGenerator.Tests/ApprovalTests/TemplateTest.cs	95.74% <0.00%> (-4.26%)	⬇️
...ft.ML.Core.Tests/UnitTests/TestResourceDownload.cs	0.00% <ø> (-75.52%)	⬇️
...est/Microsoft.ML.Predictor.Tests/TestPredictors.cs	69.62% <ø> (-0.50%)	⬇️
...ests/TrainerEstimators/MatrixFactorizationTests.cs	83.59% <0.00%> (-13.48%)	⬇️
test/Microsoft.ML.FSharp.Tests/SmokeTests.fs	77.77% <33.33%> (-10.46%)	⬇️
...est/Microsoft.ML.TestFrameworkCommon/TestCommon.cs	77.83% <40.00%> (-1.12%)	⬇️
test/Microsoft.ML.TestFramework/TestCommandBase.cs	39.41% <85.71%> (-5.55%)	⬇️
... and 68 more

[tarekgh]

LGTM. I'll let @safern and @ericstj take a look as they more familiar with such changes :-)