Change autoTuplingEnabled to only apply to tupling

Untupling of infix operators is no longer under the noAutoTupling language feature.
Instead, we always untuple if the infix operator is not unary. The idea is that, going
forward we will gradually remove infix operators that are not unary. Once that is done
completely, and there are no more backwards compatibility concerbs, the code to untuple
arguments of infix operations will become dead code and can be removed.

Author: odersky

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -2938,7 +2938,7 @@ class Typer extends Namer
      *   - we untuple tuple arguments of infix operations if the function
      *     does not consist only of unary alternatives.
      */
-    def needsTupledDual(funType: Type, pt: FunProto): Boolean = {
+    def needsTupledDual(funType: Type, pt: FunProto): Boolean =
       pt.args match
         case untpd.Tuple(elems) :: Nil =>
           elems.length > 1
@@ -2947,7 +2947,7 @@ class Typer extends Namer
         case args =>
           args.lengthCompare(1) > 0
           && isUnary(funType)
-    } && autoTuplingEnabled
+          && autoTuplingEnabled
 
     def adaptToArgs(wtp: Type, pt: FunProto): Tree = wtp match {
       case wtp: MethodOrPoly =>