`org.openjdk.jcstress.TestExecutor.VM` creates tmp files by `java.io.File:.createTempFile(String, String, FileAttribute[])`, as there is no code which removes these files and FileAttribute[] is empty (doesn't have DELETE_ON_CLOSE), we left w/ all these files in the tmp dir after test execution.

suggested fix: use DELETE_ON_CLOSE attr:
diff -r 0369dc97a8d0 jcstress-core/src/main/java/org/openjdk/jcstress/TestExecutor.java
--- a/jcstress-core/src/main/java/org/openjdk/jcstress/TestExecutor.java Wed Mar 29 13:30:12 2017 +0200
+++ b/jcstress-core/src/main/java/org/openjdk/jcstress/TestExecutor.java Thu Dec 13 13:31:27 2018 -0800
@@ -37,6 +37,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
+import java.nio.file.StandardOpenOption;
 import java.util.*;
 import java.util.concurrent.*;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -204,8 +205,8 @@
             this.pendingTasks = new ArrayList<>(configs);
             this.firstTask = pendingTasks.get(0);
             try {
- this.stdout = File.createTempFile("jcstress", "stdout");
- this.stderr = File.createTempFile("jcstress", "stderr");
+ this.stdout = File.createTempFile("jcstress", "stdout", StandardOpenOption.DELETE_ON_CLOSE);
+ this.stderr = File.createTempFile("jcstress", "stderr", StandardOpenOption.DELETE_ON_CLOSE);
             } catch (IOException e) {
                 throw new IllegalStateException(e);
             }