Add test from typelevel/scalacheck#290

tests/run/deadlock.scala

@@ -0,0 +1,11 @@
+// from https://github.com/rickynils/scalacheck/issues/290
+import scala.concurrent._
+import scala.concurrent.duration._
+import java.util.concurrent.Executors
+
+object Test {
+  import ExecutionContext.Implicits.global
+  val x = Await.result(Future(1), 1000.seconds)
+  def main(args: Array[String]) = println(x)
+}
+