Adapt i5954 tests

Adapt splice syntax and modify tests to no cancel quotes and splices before the checks

Author: nicolasstucki

tests/neg/i5954.scala

@@ -6,5 +6,5 @@ object MatcherFactory1 {
   import scala.quoted._
 
   def impl2(a: MatcherFactory1)(self: Expr[a.AndNotWord]) =
-  '{ ~self } // error: access to value a from wrong staging level
+    '{ val a: Any = $self } // error: access to value a from wrong staging level
 }

tests/pos/i5954.scala

@@ -6,10 +6,10 @@ object MatcherFactory1 {
   import scala.quoted._
 
   def impl(self: Expr[MatcherFactory1#AndNotWord]) =
-    '{ ~self }
+    '{ val a: Any = $self }
 
 
   def impl2[T: Type](a: MatcherFactory1)(self: Expr[T])(implicit ev: T =:= a.AndNotWord) =
-    '{ ~self }
+    '{ val a: Any = $self }
 
 }