optimize putIfAbsent method to computeIfAbsent which may reduce some …

[likemoongg]

[Dubbo-7542] optimize creation of Objet

What is the purpose of the change

optimize 7542
replace putIfAbsent method with computeIfAbsent to reduce extra creation of Object.

Brief changelog

Verifying this change

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[horizonzy]

LGTM.

[likemoongg]

closing this pr is a misoperation of mine ,sorry...

[horizonzy]

Some UT failed, check it.

[xiaoheng1]

LGTM