Make tests compatible with 2.12

Author: felixmulder

tests/neg/t7294.scala

@@ -0,0 +1,4 @@
+object Test {
+  // reachability error as Tuple2 is final.
+  (1, 2) match { case Seq() => 0; case _ => 1 } // error
+}

tests/pos/t5070.scala

@@ -3,7 +3,7 @@ trait A {
 }
 
 object O {
-  implicit def b(implicit x: A): x.T = error("")
+  implicit def b(implicit x: A): x.T = sys.error("")
 }
 
 class Test {

tests/pos/t7294.scala

@@ -1,11 +1,3 @@
-class Foo[t[x]<: Tuple2[Int, x]]
-
-//
-class MyPair[z](a: Int, b: z) extends Tuple2[Int, z](a,b)
-
-object foo extends Foo[MyPair]
-
-
 trait Monad[m[x <: Bound[x]], Bound[x], a] // TODO: variances!
 trait ListMonad[a] extends Monad[List, [X] => Any, a] // Dotty difference: Any is not a legal argument for hk type.
 

tests/pos/tcpoly_bounds1.scala

@@ -1,9 +1,9 @@
 import annotation.unchecked.{ uncheckedVariance=> uV }
-import scala.collection.immutable.{ListMap, HashMap, ListSet, HashSet}
+import scala.collection.mutable.{ListMap, HashMap, HashSet}
 
 object Test {
   class HashMapCollision1[A, +B](var hash: Int, var kvs: ListMap[A, B @uV]) extends HashMap[A, B @uV]
-  class HashSetCollision1[A](var hash: Int, var ks: ListSet[A]) extends HashSet[A]
+  class HashSetCollision1[A](var hash: Int, var ks: Set[A]) extends HashSet[A]
 
   def splitArray[T](ad: Array[Iterable[T]]): Any =
     ad(0) match {