Test case for the status quo in specialized traits

A deferred method in the generic interface ends up with a
corresponding, generically substituted version in the specialized
sub interface.

This is superfluous and problematic when we start adding default
methods to the interfaces. The subsequent commit will remove them.

Author: retronym

test/files/run/trait-default-specialize.check

@@ -0,0 +1,4 @@
+public abstract void T$mcI$sp.t(int)
+public abstract void T.t(java.lang.Object)
+0
+0

test/files/run/trait-default-specialize.scala

@@ -0,0 +1,14 @@
+trait T[@specialized A] {
+  def t(a: A): Unit
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    class TInt extends T[Int] { def t(a : Int) = println(a) }
+    val tMethods = classOf[TInt].getInterfaces.head.getMethods.filter(_.getName == "t")
+    println(tMethods.map(_.toString).sorted.mkString("\n"))
+    new TInt().t(0)
+    def call[A](t: T[A], a: A) = t.t(a)
+    call[Int](new TInt(), 0)
+  }
+}