[dubbo-4491]remove duplicate code in AbstractConfig.java

[zhenxianyimeng]

What is the purpose of the change

remove duplicate code in AbstractConfig.java to make brief and clean

Brief changelog

remove code ClassUtils.isPrimitive(method1.getReturnType()) in AbstractConfig.java at line 653

Verifying this change

ClassUtils.isPrimitive(method1.getReturnType()) is already judge in method MethodUtils.isGetter

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[zhenxianyimeng]

why ci build is always pending, i see it have been passed in
https://travis-ci.org/apache/dubbo/builds/555817384?utm_source=github_status&utm_medium=notification

[htynkn]

ClassUtils.isPrimitive is called

dubbo/dubbo-common/src/main/java/org/apache/dubbo/common/utils/MethodUtils.java

Line 39 in e189048

&& ClassUtils.isPrimitive(method.getReturnType());