Revert "设置时区为美国达拉斯时区"

This reverts commit a8a8895f.

xxl-job-admin/src/main/java/com/xxl/job/admin/GlobalTimeZoneConfig.java

-package com.xxl.job.admin;
-
-import org.springframework.context.annotation.Configuration;
-import org.springframework.context.annotation.Profile;
-
-import java.util.TimeZone;
-
-@Configuration
-public class GlobalTimeZoneConfig {
-
-    public GlobalTimeZoneConfig() {
-        // 设置整个Java虚拟机的默认时区
-        TimeZone.setDefault(TimeZone.getTimeZone("America/Chicago"));
-    }
-}
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