RobustScalingNormalizer entrypoint added

[michaelgsharp]

When RobustScalingNormalizer was added, PR #5166, the corresponding entrypoints were not created. This PR fixes #5309 by adding in the correct entrypoint for it.

[codecov]

Codecov Report

Merging #5310 into master will increase coverage by 0.00%.
The diff coverage is 98.63%.

@@           Coverage Diff           @@
##           master    #5310   +/-   ##
=======================================
  Coverage   73.80%   73.81%           
=======================================
  Files        1022     1022           
  Lines      190617   190690   +73     
  Branches    20488    20489    +1     
=======================================
+ Hits       140686   140755   +69     
- Misses      44411    44413    +2     
- Partials     5520     5522    +2     

Flag	Coverage Δ
#Debug	73.81% <98.63%> (+<0.01%)	⬆️
#production	69.56% <95.83%> (+<0.01%)	⬆️
#test	87.67% <100.00%> (+0.01%)	⬆️

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

Impacted Files	Coverage Δ
...rc/Microsoft.ML.Data/Transforms/NormalizeColumn.cs	62.32% <93.75%> (+1.15%)	⬆️
src/Microsoft.ML.Data/Transforms/NormalizeUtils.cs	50.79% <100.00%> (+7.15%)	⬆️
...crosoft.ML.Core.Tests/UnitTests/TestEntryPoints.cs	98.45% <100.00%> (+0.01%)	⬆️
...c/Microsoft.ML.FastTree/Utils/ThreadTaskManager.cs	79.48% <0.00%> (-20.52%)	⬇️
...rosoft.ML.AutoML/ColumnInference/TextFileSample.cs	59.60% <0.00%> (-2.65%)	⬇️
...ML.Transforms/Text/StopWordsRemovingTransformer.cs	86.67% <0.00%> (+0.14%)	⬆️
....ML.AutoML/PipelineSuggesters/PipelineSuggester.cs	84.03% <0.00%> (+0.84%)	⬆️
...icrosoft.ML.AutoML/Experiment/SuggestedPipeline.cs	92.78% <0.00%> (+4.12%)	⬆️