JUnitReportReporter is too slow

[spkrka]

TestNG Version

Note: only the latest version is supported
Tested with 7.6.1 as well as manual builds from latest master

Expected behavior

JUnitReportReporter finishes in under a second.

Actual behavior

JUnitReportReporter takes over 140 seconds to run.

Output

10:20:51.969 [main] INFO  org.testng.internal.Utils - [TestNG] Time taken by org.testng.internal.ExitCodeListener@78b0ec3a: 0 ms
10:20:51.984 [main] INFO  org.testng.internal.Utils - [TestNG] Time taken by org.testng.reporters.SuiteHTMLReporter@642c6461: 15 ms
10:20:52.034 [main] INFO  org.testng.internal.Utils - [TestNG] Time taken by org.testng.reporters.jq.Main@2b44605c: 50 ms
10:20:52.034 [main] INFO  org.testng.internal.Utils - [TestNG] Time taken by org.testng.reporters.FailedReporter@55421b8d: 0 ms
10:20:52.062 [main] INFO  org.testng.internal.Utils - [TestNG] Time taken by org.testng.reporters.XMLReporter@13e00016: 28 ms
10:20:52.076 [main] INFO  org.testng.internal.Utils - [TestNG] Time taken by org.testng.reporters.EmailableReporter2@3f0ce0d1: 14 ms
10:23:13.320 [main] INFO  org.testng.internal.Utils - [TestNG] Time taken by org.testng.reporters.JUnitReportReporter@566c1e71: 141244 ms

The produced reports are about 400 KiB in size total, with 98 xml files and 592 test cases.

I have connected to the process with VisualVM and run the sampler. It shows that ~100% of the time is spent in getHostName(). I can make a PR to run that once instead of for every test case.

[spkrka]

After applying #2802 I can observe:

10:50:21.541 [main] INFO  org.testng.internal.Utils - [TestNG] Time taken by org.testng.reporters.JUnitReportReporter@6bcdd6e4: 775 ms