[Java] Remove high explicit idleSleepDurationNs from tests.

It doesn't seem necessary, and removing it makes the tests much faster (timings from my laptop):

PubAndSubTest 29s to 17s
PublicationRevokeTest 5s to 3s

(cherry picked from commit cdcfd4b)

Author: wojciech-adaptive

aeron-system-tests/src/test/java/io/aeron/PubAndSubTest.java

@@ -92,8 +92,7 @@ private static List<String> channels()
         .timerIntervalNs(MILLISECONDS.toNanos(100));
 
     private final Aeron.Context clientContext = new Aeron.Context()
-        .resourceLingerDurationNs(MILLISECONDS.toNanos(200))
-        .idleSleepDurationNs(MILLISECONDS.toNanos(100));
+        .resourceLingerDurationNs(MILLISECONDS.toNanos(200));
 
     private Aeron publishingClient;
     private Aeron subscribingClient;

aeron-system-tests/src/test/java/io/aeron/PublicationRevokeTest.java

@@ -73,8 +73,7 @@ class PublicationRevokeTest
         .threadingMode(ThreadingMode.SHARED);
 
     private final Aeron.Context clientContext = new Aeron.Context()
-        .resourceLingerDurationNs(MILLISECONDS.toNanos(200))
-        .idleSleepDurationNs(MILLISECONDS.toNanos(100));
+        .resourceLingerDurationNs(MILLISECONDS.toNanos(200));
 
     private Aeron client;
     private TestMediaDriver driver;