Change ArraySortHelper to use Comparison<T>

Change ArraySortHelper to use Comparison<T>

The Array/List.Sort overloads that take a Comparison<T> have worse performance than the ones that take a IComparer<T>. That's because sorting is implemented around IComparer<T> and a Comparison<T> needs to be wrapped in a comparer object to be used.

At the same time, interface calls are slower than delegate calls so the existing implementation doesn't offer the best performance even when the IComparer<T> based overloads are used.

By changing the implementation to use Comparison<T> we avoid interface calls in both cases.

When IComparer<T> overloads are used a Comparison<T> delegate is created from IComparer<T>.Compare, that's an extra object allocation but sorting is faster and we avoid having two separate sorting implementations.

Commit migrated from https://github.com/dotnet/coreclr/commit/1cf86165849ffb0ab909078ef09f124f898f0461