Remove broken SelectorSystem#steal impl

core/jvm/src/main/scala/cats/effect/unsafe/SelectorSystem.scala

@@ -19,9 +19,8 @@ package unsafe
 
 import scala.util.control.NonFatal
 
-import java.nio.channels.{ClosedSelectorException, SelectableChannel}
+import java.nio.channels.SelectableChannel
 import java.nio.channels.spi.{AbstractSelector, SelectorProvider}
-import java.util.ConcurrentModificationException
 
 import SelectorSystem._
 
@@ -99,60 +98,8 @@ final class SelectorSystem private (provider: SelectorProvider) extends PollingS
     } else false
   }
 
-  def steal(poller: Poller, reportFailure: Throwable => Unit): Boolean = {
-    val selector = poller.selector
-
-    val keys =
-      try {
-        if (selector.isOpen()) {
-          selector.selectNow()
-          selector.selectedKeys()
-        } else return false
-      } catch { // selector closed concurrently
-        case _: ClosedSelectorException => return false
-      }
-
-    var polled = false
-    val ready = keys.iterator()
-
-    try {
-      while (ready.hasNext()) {
-        val key = ready.next()
-
-        var readyOps = 0
-        var error: Throwable = null
-        try {
-          readyOps = key.readyOps()
-        } catch {
-          case ex if NonFatal(ex) =>
-            error = ex
-            readyOps = -1 // notify all waiters
-        }
-
-        val value = if (error ne null) Left(error) else Right(readyOps)
-
-        var node = key.attachment().asInstanceOf[CallbackNode]
-        while (node ne null) {
-          val next = node.next
-
-          if ((node.interest & readyOps) != 0) { // execute callback
-            val cb = node.callback
-            if (cb != null) {
-              cb(value)
-              polled = true
-            }
-          }
-
-          node = next
-        }
-      }
-    } catch {
-      case _: ConcurrentModificationException =>
-      // owner thread concurrently processing selected keys, so suppress and exit loop
-    }
-
-    polled
-  }
+  def steal(poller: Poller, reportFailure: Throwable => Unit): Boolean =
+    false
 
   def needsPoll(poller: Poller): Boolean =
     !poller.selector.keys().isEmpty()