HADOOP-17625. Update to Jetty 9.4.39. (#2870)

Reviewed-by: cxorm <lianp964@gmail.com>
(cherry picked from commit 6040e86)

Author: jojochuang

hadoop-project/pom.xml

@@ -37,7 +37,7 @@
     <!--Whether to proceed to next module if any test failures exist-->
     <ignoreTestFailure>true</ignoreTestFailure>
     <maven.test.redirectTestOutputToFile>true</maven.test.redirectTestOutputToFile>
-    <jetty.version>9.4.35.v20201120</jetty.version>
+    <jetty.version>9.4.39.v20210325</jetty.version>
     <test.exclude>_</test.exclude>
     <test.exclude.pattern>_</test.exclude.pattern>