Revert check files

These should also be converted to `using` once Tasty printers have been updated.

Author: odersky

tests/run-staging/quote-nested-2.check

@@ -1,4 +1,4 @@
-((using qctx: scala.quoted.QuoteContext) => {
+((qctx: scala.quoted.QuoteContext) ?=> {
   val a: scala.quoted.Expr[scala.Int] = scala.internal.quoted.CompileTime.exprQuote[scala.Int](4).apply(using qctx)
-  ((using qctx1_$1: scala.quoted.QuoteContext) => a).apply(using qctx)
+  ((qctx1_$1: scala.quoted.QuoteContext) ?=> a).apply(using qctx)
 })

tests/run-staging/quote-nested-5.check

@@ -1,4 +1,4 @@
-((using qctx: scala.quoted.QuoteContext) => {
+((qctx: scala.quoted.QuoteContext) ?=> {
   val a: scala.quoted.Expr[scala.Int] = scala.internal.quoted.CompileTime.exprQuote[scala.Int](4).apply(using qctx)
-  ((using qctx2: scala.quoted.QuoteContext) => ((using qctx1_$1: scala.quoted.QuoteContext) => a).apply(using qctx2)).apply(using qctx)
+  ((qctx2: scala.quoted.QuoteContext) ?=> ((qctx1_$1: scala.quoted.QuoteContext) ?=> a).apply(using qctx2)).apply(using qctx)
 })