Update AsyncSeq.fs

Author: njlr

src/FSharp.Control.AsyncSeq/AsyncSeq.fs

@@ -1414,6 +1414,7 @@ module AsyncSeq =
       if (buffer.Count > 0) then
           yield buffer.ToArray() }
 
+  #if !FABLE_COMPILER
   let toSortedSeq fn source =
     toArrayAsync source |> Async.map fn |> Async.RunSynchronously
 
@@ -1428,6 +1429,7 @@ module AsyncSeq =
 
   let sortByDescending (projection:'T -> 'Key) (source:AsyncSeq<'T>) : array<'T> when 'Key : comparison =
     toSortedSeq (Array.sortByDescending projection) source
+  #endif
 
   #if !FABLE_COMPILER
   let bufferByCountAndTime (bufferSize:int) (timeoutMs:int) (source:AsyncSeq<'T>) : AsyncSeq<'T[]> =