Revert "Fix tests"

This reverts commit 1bbb255.

# Conflicts:
#	library/src-bootstrapped/scala/internal/quoted/Expr.scala
#	tests/run-macros/i9812b/Macro_1.scala
#	tests/run-staging/quote-nested-1.scala

Author: odersky

tests/neg/i2006.scala

@@ -4,7 +4,7 @@ object Test {
   inline def bar(f: Int ?=> Int) = f // error
 
   def main(args: Array[String]) = {
-    foo((using thisTransaction) => 43)
-    bar((using thisTransaction) => 44)
+    foo(thisTransaction ?=> 43)
+    bar(thisTransaction ?=> 44)
   }
 }

tests/neg/i2146.scala

@@ -1,5 +1,5 @@
 class Test {
-  def foo[A, B]: A ?=> B ?=> Int = { (using b: B) =>  // error: found Int, required: A ?=> B ?=> Int
+  def foo[A, B]: A ?=> B ?=> Int = { (b: B) ?=>  // error: found Int, required: A ?=> B ?=> Int
     42
   }
 }

tests/neg/i4668.scala

@@ -8,4 +8,4 @@ trait Functor[F[_]] { def map[A,B](x: F[A])(f: A => B): F[B] }
 object Functor { implicit object listFun extends Functor[List] { def map[A,B](ls: List[A])(f: A => B) = ls.map(f) } }
 
 val map: (A:Type,B:Type,F:Type1) ?=>  (Functor[F.T]) ?=> (F.T[A.T]) => (A.T => B.T) => F.T[B.T] =
-  (using fun) => (using x) => f => fun.map(x)(f) // error
+  fun ?=> x => f => fun.map(x)(f) // error

tests/neg/scoped-quoted-expr-proto.scala

@@ -69,7 +69,7 @@ package b {
       }
     }
 
-    r { (using qctx) =>
+    r { qctx ?=>
       var escaped: qctx.Expr[Double] = ???
       q{ (x: Double) =>
         s{
@@ -127,7 +127,7 @@ package c {
       }
     }
 
-    r { (using qctx) =>
+    r { qctx ?=>
       var escaped: qctx.Expr[Double] = ???
       q{ (x: Double) =>
         s{

tests/pos/case-getters.scala

@@ -1,6 +1,6 @@
 case class Foo(x: 1, y: Int ?=> Int)
 object Test {
-  val f = Foo(1, (using i: Int) => i)
+  val f = Foo(1, (i: Int) ?=> i)
   val fx1: 1 = f.x
   val fx2: 1 = f._1
   val fy1: Int = f.y(using 1)

tests/pos/i5966.scala

@@ -1,5 +1,5 @@
 object Test {
-  def foo = (using v: Int) => (x: Int) => v + x
+  def foo = (v: Int) ?=> (x: Int) => v + x
   given myInt as Int = 4
 
   foo.apply(1)

tests/pos/i6863/lib_1.scala

@@ -1,2 +1,2 @@
 trait Ctx
-inline def foo(): Unit = (using x: Ctx) => ()
+inline def foo(): Unit = (x: Ctx) ?=> ()

tests/pos/ift-assign.scala

@@ -1,7 +1,7 @@
 class Context
 
 object Test {
-  var f: Context ?=> String = ((using _) => "")
+  var f: Context ?=> String = (_ ?=> "")
 
   f = f
 

tests/pos/inline-apply.scala

@@ -5,7 +5,7 @@ object Test {
   def transform()(implicit ctx: Context) = {
     inline def withLocalOwner[T](op: Context ?=> T) = op(using ctx)
 
-    withLocalOwner { (using ctx) => }
+    withLocalOwner { ctx ?=> }
 
   }
 }

tests/pos/reference/delegates.scala

@@ -78,12 +78,12 @@ object Instances extends Common:
     println(minimum(xs))
 
   case class Context(value: String)
-  val c0: Context ?=> String = (using ctx) => ctx.value
-  val c1: Context ?=> String = (using ctx: Context) => ctx.value
+  val c0: Context ?=> String = ctx ?=> ctx.value
+  val c1: Context ?=> String = (ctx: Context) ?=> ctx.value
 
   class A
   class B
-  val ab: (x: A, y: B) ?=> Int = (using a: A, b: B) => 22
+  val ab: (x: A, y: B) ?=> Int = (a: A, b: B) ?=> 22
 
   trait TastyAPI:
     type Symbol