Remove dead code for ordering PreprocessedSources (#2103)

Author: MaciejG604

modules/build/src/main/scala/scala/build/preprocessing/PreprocessedSource.scala

@@ -71,36 +71,4 @@ object PreprocessedSource {
       ScopePath.fromPath(path)
     def directivesPositions: None.type = None
   }
-
-  private def index(s: PreprocessedSource): Int =
-    s match {
-      case _: NoSourceCode => 0
-      case _: InMemory     => 1
-      case _: OnDisk       => 2
-    }
-
-  implicit val ordering: Ordering[PreprocessedSource] =
-    new Ordering[PreprocessedSource] {
-      def compare(a: PreprocessedSource, b: PreprocessedSource): Int = {
-        val aIdx   = index(a)
-        val bIdx   = index(b)
-        val idxCmp = aIdx.compare(bIdx)
-        if (idxCmp == 0)
-          (a, b) match {
-            case (a0: NoSourceCode, b0: NoSourceCode) =>
-              a0.path.toString.compareTo(b0.path.toString)
-            case (a0: InMemory, b0: InMemory) =>
-              (a0.reportingPath, b0.reportingPath) match {
-                case (Left(ap), Left(bp))   => ap.compareTo(bp)
-                case (Left(_), Right(_))    => -1
-                case (Right(ap), Right(bp)) => ap.toString.compareTo(bp.toString)
-                case (Right(_), Left(_))    => 1
-              }
-            case (a0: OnDisk, b0: OnDisk) => a0.path.toString.compareTo(b0.path.toString)
-            case _                        => ???
-          }
-        else idxCmp
-      }
-    }
-
 }