[XABT] Use SortedSets in JCWGenerator.EnsureIdenticalCollections for better performance.

[jpobst]

JCWGenerator.EnsureIdenticalCollections ensures that every architecture being built contains the same Java derived types. Because this includes Mono.Android.dll, even the dotnet new android template has ~8500 Java types found. The current implementation uses nested loops and is O(N²). By first sorting the items into SortedSet types and then using SetEquals we can significantly speed up this operation.

Fresh dotnet build of Android template (defaults to 4 architectures), EnsureIdenticalCollections takes:

main	3081 ms
PR	29 ms

[jonathanpeppers]

One trick, I've been doing to ensure there are no closures:

Suggested change

	var templateSet = new SortedSet<string> (templateState.AllJavaTypes.Select (t => t.FullName), StringComparer.Ordinal);
	var typesSet = new SortedSet<string> (state.AllJavaTypes.Select (t => t.FullName), StringComparer.Ordinal);
	var templateSet = new SortedSet<string> (templateState.AllJavaTypes.Select (static t => t.FullName), StringComparer.Ordinal);
	var typesSet = new SortedSet<string> (state.AllJavaTypes.Select (static t => t.FullName), StringComparer.Ordinal);

This wouldn't compile if you captured a variable on accident.

These are so short, though, it's fine as-is.

[jonathanpeppers]

I'm going to merge as-is, to better test build performance in 9.