Fix switchBackDelayNs failure problem in class of AutoClusterFailover

[lordcheng10]

Motivation

Consider such a bad case:

1. When the following line of code is executed, switch secondary to primary:
   

   pulsar/pulsar-client/src/main/java/org/apache/pulsar/client/impl/AutoClusterFailover.java

   Lines 104 to 106 in ced5786

   	// current service url is secondary, probe whether it is down
   	probeAndUpdateServiceUrl(primary, primaryAuthentication, primaryTlsTrustCertsFilePath,
   	primaryTlsTrustStorePath, primaryTlsTrustStorePassword);

2. The currentPulsarServiceUrl at this time is primary, and then the probeAndCheckSwitchBack method is executed immediately, in which the recoverTimestamp timestamp will be updated:
   

   pulsar/pulsar-client/src/main/java/org/apache/pulsar/client/impl/AutoClusterFailover.java

   Lines 248 to 250 in ced5786

   	if (recoverTimestamp == -1) {
   	recoverTimestamp = currentTimestamp;
   	} else if (currentTimestamp - recoverTimestamp >= switchBackDelayNs) {

3. When the primary is switched to the secondary again and the probeAndCheckSwitchBack method is executed, the switchBackDelayNs parameter will be invalid, because the recoverTimestamp has been updated again and is no longer equal to -1;

So we need to judge currentPulsarServiceUrl.equals(primary) again before executing probeAndCheckSwitchBack();

Documentation

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[hangc0276]

@lordcheng10 Nice catch, thanks for your contribution. Would you please help add a test to protect the switch back delay logic?

[lordcheng10]

@lordcheng10 Nice catch, thanks for your contribution. Would you please help add a test to protect the switch back delay logic?

OK ,I will add unit test

[lordcheng10]

@lordcheng10 Nice catch, thanks for your contribution. Would you please help add a test to protect the switch back delay logic?

Done

[lordcheng10]

@hangc0276 @codelipenghui PTAL,thanks!

[lordcheng10]

/pulsarbot run-failure-checks

[lordcheng10]

/pulsarbot run-failure-checks

[lordcheng10]

@codelipenghui PTAL,thanks!