Replaced some Dictionaries and Hashtables with Hashsets

[ThomasGoulet73]

I replaced some Dictionaries and Hashtables that only use the key as a way to filter out duplicates. I replaced them with HashSet to improve performance.

I used the following code to benchmark it :
https://gist.github.com/ThomasGoulet73/99559a6cd49a04dc70a413e9668eee22

Here are the results (First row is 10 items, second is 1000 and third is 100000) :

Dictionary vs HashSet:

Method	enumerable	Mean	Error	StdDev	Ratio	RatioSD	Gen 0	Gen 1	Gen 2	Allocated
Dictionary	Syste(...)ring] [48]	742.2 ns	14.71 ns	13.76 ns	1.00	0.00	0.2270	0.0010	-	1.39 KB
Dictionary	Syste(...)ring] [48]	60,340.7 ns	231.42 ns	216.47 ns	81.32	1.42	18.8599	4.6997	-	116.13 KB
Dictionary	Syste(...)ring] [48]	6,990,405.3 ns	114,642.24 ns	101,627.36 ns	9,405.37	234.34	796.8750	750.0000	742.1875	10303.12 KB
HashSet	Syste(...)ring] [48]	558.8 ns	1.55 ns	1.45 ns	0.75	0.01	0.1907	-	-	1.17 KB
HashSet	Syste(...)ring] [48]	47,343.1 ns	173.14 ns	161.96 ns	63.81	1.22	14.2822	2.8076	-	87.76 KB
HashSet	Syste(...)ring] [48]	5,982,708.5 ns	80,465.49 ns	75,267.47 ns	8,062.82	161.97	703.1250	648.4375	648.4375	7945.69 KB

Hashtable vs HashSet:

Method	enumerable	Mean	Error	StdDev	Ratio	RatioSD	Gen 0	Gen 1	Gen 2	Allocated
HashHashtable	Syste(...)ring] [48]	680.6 ns	3.88 ns	3.44 ns	1.00	0.00	0.1326	-	-	832 B
HashHashtable	Syste(...)ring] [48]	94,554.4 ns	477.01 ns	372.42 ns	138.79	0.76	13.7939	3.4180	-	87472 B
HashHashtable	Syste(...)ring] [48]	13,670,183.4 ns	145,574.93 ns	129,048.39 ns	20,086.21	188.35	640.6250	640.6250	640.6250	7244564 B
HashSet	Syste(...)ring] [48]	379.2 ns	2.95 ns	2.76 ns	0.56	0.00	0.1287	0.0005	-	808 B
HashSet	Syste(...)ring] [48]	36,610.4 ns	152.59 ns	142.74 ns	53.79	0.40	11.5967	2.8687	-	73200 B
HashSet	Syste(...)ring] [48]	4,631,696.9 ns	63,645.40 ns	53,146.79 ns	6,801.30	90.29	562.5000	523.4375	523.4375	6038279 B

I think the perf gain is good enough to consider this PR.

Thank you!

[ThomasGoulet73]

Hey @ryalanms, the CI failed and it doesn't seem to be related to my changes. When you have a few minutes, could you run it again ? I don't think external contributors have the permissions to do it.

Thank you!

[ryalanms]

@ThomasGoulet73: Yes, I'll fix this today. A VS version update on the build pool machines can cause a compiler version mismatch with the internal WPF build. The internal WPF build needs to be triggered.

[ryalanms]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[ryalanms]

This and @wjk's changes had to be tested separately from the others in the community test pass.

[ThomasGoulet73]

Thank you @ryalanms!