Fix problem in fastparse test

[odersky]

With #7130, line 117 in the fastparse test FasterParserParser.scala broke. It's the first commented-out line in the code snippet:

  def arrBody[$: P]: P[Expr] = P(
    Index ~~ expr ~ (compSuffix | "," ~ (compSuffix | (expr.rep(0, sep = ",") ~ ",".?).map(Right(_)))).?
  ).map{
    case (offset, first, None) => Expr.Arr(offset, Seq(first))
    //case (offset, first, Some(Left(comp))) => Expr.Comp(offset, first, comp._1, comp._2)
      // previous line gives an error after #7130:
      //   _1 is not a member of Any (with errors ^^^^ under comp._1)
    case (offset, first, Some(Right(rest))) => Expr.Arr(offset, Seq(first) ++ rest)
  }

We should find out how to fix this.

[liufengyun]

Already fixed in #7161.