当连接信息出错后异常没有往外抛出无限打印error信息

DruidDataSource-->DestroyConnectionThread
```java
public void run() {
initedLatch.countDown();

long lastDiscardCount = 0;
int errorCount = 0;
for (;;) {
// addLast
try {
lock.lockInterruptibly();
} catch (InterruptedException e2) {
break;
}

long discardCount = DruidDataSource.this.discardCount;
boolean discardChanged = discardCount - lastDiscardCount > 0;
lastDiscardCount = discardCount;

try {
boolean emptyWait = true;

if (createError != null
&& poolingCount == 0
&& !discardChanged) {
emptyWait = false;
}

if (emptyWait
&& asyncInit && createCount < initialSize) {
emptyWait = false;
}

if (emptyWait) {
// 必须存在线程等待，才创建连接
if (poolingCount >= notEmptyWaitThreadCount //
&& !(keepAlive && activeCount + poolingCount < minIdle)) {
empty.await();
}

// 防止创建超过maxActive数量的连接
if (activeCount + poolingCount >= maxActive) {
empty.await();
continue;
}
}

} catch (InterruptedException e) {
lastCreateError = e;
lastErrorTimeMillis = System.currentTimeMillis();

if (!closing) {
LOG.error("create connection Thread Interrupted, url: " + jdbcUrl, e);
}
break;
} finally {
lock.unlock();
}

PhysicalConnectionInfo connection = null;

try {
connection = createPhysicalConnection();
} catch (SQLException e) {
LOG.error("create connection SQLException, url: " + jdbcUrl + ", errorCode " + e.getErrorCode()
+ ", state " + e.getSQLState(), e);

errorCount++;
if (errorCount > connectionErrorRetryAttempts && timeBetweenConnectErrorMillis > 0) {
// fail over retry attempts
setFailContinuous(true);
if (failFast) {
lock.lock();
try {
notEmpty.signalAll();
} finally {
lock.unlock();
}
}

if (breakAfterAcquireFailure) {
break;
}

try {
Thread.sleep(timeBetweenConnectErrorMillis);
} catch (InterruptedException interruptEx) {
break;
}
}
//这里没有else处理，控制台一直打钱error信息.connectionErrorRetryAttempts默认为1.
} catch (RuntimeException e) {
LOG.error("create connection RuntimeException", e);
setFailContinuous(true);
continue;
} catch (Error e) {
LOG.error("create connection Error", e);
setFailContinuous(true);
break;
}

if (connection == null) {
continue; // 这里退出循环，errorCount一直++
}

boolean result = put(connection);
if (!result) {
JdbcUtils.close(connection.getPhysicalConnection());
LOG.info("put physical connection to pool failed.");
}

errorCount = 0; // reset errorCount
}
}
}
```

这个本身在调试开发过程中没有问题，console会打印出错信息，人工可以停止。
当做ci时，gradle build默认执行测试代码，默认不打印log信息到控制台。数据库连接不上时，会卡在上面的for循环，一直执行。造成查找错误信息困难。

建议增大connectionErrorRetryAttempts默认值，加上else处理异常。

Start in DruidDataSource.DestroyConnectionThread.run and inspect the SQLException retry path, especially connectionErrorRetryAttempts and the handling after createPhysicalConnection() returns null. Run the relevant Gradle tests with the database unavailable and verify that failures do not loop indefinitely, while the connection error remains findable.

Written by the indexing model from the issue text.