$ rm -rf JT*; jtreg -jdk:../../../../../../jdk1.8.0_212/ -va sun/tools/jconsole/WorkerDeadlockTest.java
STDOUT:
STDERR:
/home/hedongbo/myprojects/openJDK/jdk8u-dev/jdk/test/sun/tools/jconsole/WorkerDeadlockTest.java:33: error: package sun.tools.jconsole does not exist
import sun.tools.jconsole.Worker;
                         ^
/home/hedongbo/myprojects/openJDK/jdk8u-dev/jdk/test/sun/tools/jconsole/WorkerDeadlockTest.java:42: error: cannot find symbol
            Worker worker = new Worker("worker-" + i);
            ^
  symbol: class Worker
  location: class WorkerDeadlockTest
/home/hedongbo/myprojects/openJDK/jdk8u-dev/jdk/test/sun/tools/jconsole/WorkerDeadlockTest.java:42: error: cannot find symbol
            Worker worker = new Worker("worker-" + i);
                                ^
  symbol: class Worker
  location: class WorkerDeadlockTest
3 errors

TEST RESULT: Failed. Compilation failed: Compilation failed
--------------------------------------------------
Test results: failed: 1

$ rm -rf JT*; jtreg -jdk:/home/hedongbo/software/jdk1.8.0_212 sun/tools/jconsole/WorkerDeadlockTest.java
Directory "JTwork" not found: creating
Directory "JTreport" not found: creating
Test results: passed: 1

$ cat sun/tools/jconsole/WorkerDeadlockTest.java
/**
 * @test
 * @bug 8236872
 * @summary The test tries to catch a deadlock by creating a new worker,
 * starting it, adding an empty job and immediately stopping it.
 * @library ${java.home}/lib/jconsole.jar
 * @run main WorkerDeadlockTest
 */
import sun.tools.jconsole.Worker;
public class WorkerDeadlockTest {
    private static final int REPEAT_NUMBER = 1000;
    public static void main(String[] args) {
        for (int i = 1; i < REPEAT_NUMBER; i++) {
            Worker worker = new Worker("worker-" + i);
            worker.start();
            worker.add(() -> { });
            worker.stopWorker();
            System.out.println("Worker " + i + " was successfully stopped");
        }
    }
}

The reason for the error is that the working directory of jtreg is JTwork/scratch, which causes the relative path to fail.

As can be seen from Locations.java:262, jtreg hopes to get the absolute path of the library, so it is recommended to modify the code as follows:
diff -r ff9fdaab4344 src/share/classes/com/sun/javatest/regtest/config/Locations.java
--- a/src/share/classes/com/sun/javatest/regtest/config/Locations.java Tue Sep 15 15:23:52 2020 -0700
+++ b/src/share/classes/com/sun/javatest/regtest/config/Locations.java Sat Oct 17 02:38:18 2020 +0800
@@ -253,7 +253,7 @@
                 String name = lib.substring(2, end);
                 File dir = null;
                 if (name.equals("java.home")) {
- dir = testJDK.getFile();
+ dir = testJDK.getAbsoluteFile();
                 } else if (name.equals("jtreg.home")) {
                     dir = jtpath.asList().get(0).getParentFile().getParentFile();
                 }