Move test from neg to pos

Now type inference does not infer `~t` anymore, now it infers `T`
which is phase correct. Writing `~t` explicitly still fails as
expected (tests/neg/i4774b.scala).

Author: nicolasstucki

tests/neg/i4774a.scala renamed to tests/pos/i4774a.scala

@@ -4,8 +4,6 @@ import scala.quoted._
 object Test {
   def loop[T](x: Expr[T])(implicit t: Type[T]): Expr[T] = '{
     val y: ~t = ~x
-    ~loop( // error: inferred loop[~t] where T should be used
-      '(y)
-    )
+    ~loop('(y))
   }
 }