Simplify exception handling in safeRun method

Refactor safeRun method to simplify exception handling.
cleaned up the code which was mistyped

Author: bitflicker64

hugegraph-server/hugegraph-core/src/main/java/org/apache/hugegraph/util/Consumers.java

@@ -111,22 +111,10 @@ public void start(String name) {
 
     private Void safeRun() {
         try {
-            this.runAndDone();
-        } catch (Throwable e) {
-            LOG.error("Worker failed in ContextCallable wrapper", e);
-            if (this.exception == null) {
-                this.exception = e;
-            }
-        } catch (Throwable e) {
-            LOG.error("Worker failed before runAndDone()", e);
-            if (this.exception == null) {
-                this.exception = e;
-            }
-            // exceptionHandle(e) will be called inside runAndDone()
+            return this.runAndDone();
         } finally {
             this.latch.countDown();
         }
-        return null;
     }
 
     private Void runAndDone() {