Fix LockRegLeaderIn for interrupted Thread.sleep (#2455)

* Fix LockRegLeaderIn for interrupted Thread.sleep

https://build.spring.io/browse/INT-FATS5IC-517

If current thread is interrupted, the `Thread.sleep()` interrupts
immediately.
In the catch block of the main loop in the `LockRegistryLeaderInitiator`
we have such a dangerous `sleep()` and don't restart election in this
candidate any more

* Move `Thread.sleep()` to else after checking the current thread for
interrupted state
* Remove `LongRunningIntegrationTest` rule from the
`RedisLockRegistryLeaderInitiatorTests` since it now works much faster
after proper `busy-wait` handling

**Cherry-pick to master**

* Ignore interruption on the sleep i catch and move on with loop

spring-integration-core/src/main/java/org/springframework/integration/support/leader/LockRegistryLeaderInitiator.java

@@ -397,10 +397,6 @@ else if (acquired) {
 							}
 							// The lock was broken and we are no longer leader
 							handleRevoked();
-							if (isRunning()) {
-								// Give it a chance to elect some other leader.
-								Thread.sleep(LockRegistryLeaderInitiator.this.busyWaitMillis);
-							}
 						}
 
 						if (e instanceof InterruptedException || Thread.currentThread().isInterrupted()) {
@@ -417,9 +413,21 @@ else if (acquired) {
 							}
 							return null;
 						}
-						else if (logger.isDebugEnabled()) {
-							logger.debug("Error acquiring the lock for " + this.context +
-									". " + (isRunning() ? "Retrying..." : ""), e);
+						else {
+							if (isRunning()) {
+								// Give it a chance to elect some other leader.
+								try {
+									Thread.sleep(LockRegistryLeaderInitiator.this.busyWaitMillis);
+								}
+								catch (InterruptedException e1) {
+									// Ignore interruption and let it to be caught on the next cycle.
+									Thread.currentThread().interrupt();
+								}
+							}
+							if (logger.isDebugEnabled()) {
+								logger.debug("Error acquiring the lock for " + this.context +
+										". " + (isRunning() ? "Retrying..." : ""), e);
+							}
 						}
 					}
 				}

spring-integration-redis/src/test/java/org/springframework/integration/redis/leader/RedisLockRegistryLeaderInitiatorTests.java

@@ -37,7 +37,6 @@
 import org.springframework.integration.redis.util.RedisLockRegistry;
 import org.springframework.integration.support.leader.LockRegistryLeaderInitiator;
 import org.springframework.integration.test.rule.Log4j2LevelAdjuster;
-import org.springframework.integration.test.support.LongRunningIntegrationTest;
 import org.springframework.scheduling.concurrent.CustomizableThreadFactory;
 
 /**
@@ -49,9 +48,6 @@
  */
 public class RedisLockRegistryLeaderInitiatorTests extends RedisAvailableTests {
 
-	@Rule
-	public LongRunningIntegrationTest longTests = new LongRunningIntegrationTest();
-
 	@Rule
 	public Log4j2LevelAdjuster adjuster =
 			Log4j2LevelAdjuster.trace()