Onnx conversion theory

[sharwell]

Use [Theory] to break up tests in OnnxConversionTest.

📝 Builds on #4532 and #4545

💡 Recommended review strategy is commit-by-commit. The final commit is easier to review with whitespace-only changes hidden.

[codemzs]

I assume it will infer all possible values in this case since they are discrete?

[codemzs]

[codecov]

Codecov Report

Merging #4533 into master will decrease coverage by 0.02%.
The diff coverage is 96.2%.

@@            Coverage Diff             @@
##           master    #4533      +/-   ##
==========================================
- Coverage   75.13%   75.11%   -0.03%     
==========================================
  Files         908      908              
  Lines      160238   160163      -75     
  Branches    17256    17250       -6     
==========================================
- Hits       120401   120307      -94     
- Misses      35016    35040      +24     
+ Partials     4821     4816       -5

Flag	Coverage Δ
#Debug	75.11% <96.2%> (-0.03%)	⬇️
#production	70.52% <ø> (-0.02%)	⬇️
#test	90.3% <96.2%> (-0.02%)	⬇️

Impacted Files	Coverage Δ
test/Microsoft.ML.Tests/OnnxConversionTest.cs	95.54% <96.2%> (-0.32%)	⬇️
...c/Microsoft.ML.FastTree/Utils/ThreadTaskManager.cs	79.48% <0%> (-20.52%)	⬇️
src/Microsoft.ML.Core/Data/ProgressReporter.cs	70.95% <0%> (-6.99%)	⬇️
...rosoft.ML.AutoML/ColumnInference/TextFileSample.cs	59.6% <0%> (-2.65%)	⬇️
...ML.Transforms/Text/StopWordsRemovingTransformer.cs	86.1% <0%> (-0.16%)	⬇️
...soft.ML.Data/DataLoadSave/Text/TextLoaderCursor.cs	85.11% <0%> (+0.4%)	⬆️
src/Microsoft.ML.AutoML/Sweepers/Parameters.cs	83.89% <0%> (+0.84%)	⬆️
...icrosoft.ML.AutoML/Experiment/SuggestedPipeline.cs	92.78% <0%> (+4.12%)	⬆️
....ML.AutoML/PipelineSuggesters/PipelineSuggester.cs	87.39% <0%> (+4.2%)	⬆️