8292315: Tests should not rely on specific JAR file names (hotspot)

Reviewed-by: phh
Backport-of: 62a7fc60d3b3a27525fc01930834dab6f89bd451

test/hotspot/jtreg/runtime/cds/appcds/dynamicArchive/CDSStreamTestDriver.java

@@ -37,6 +37,7 @@
 
 import org.testng.annotations.Test;
 import java.io.File;
+import java.nio.file.Path;
 import jtreg.SkippedException;
 import sun.hotspot.gc.GC;
 
@@ -49,22 +50,14 @@ public void testMain() throws Exception {
 
     private static final String classDir = System.getProperty("test.classes");
     private static final String mainClass = "TestStreamApp";
-    private static final String javaClassPath = System.getProperty("java.class.path");
     private static final String ps = System.getProperty("path.separator");
     private static final String skippedException = "jtreg.SkippedException: Unable to map shared archive: test did not complete";
 
     static void doTest() throws Exception {
         String topArchiveName = getNewArchiveName();
         String appJar = JarBuilder.build("streamapp", new File(classDir), null);
 
-        String[] classPaths = javaClassPath.split(File.pathSeparator);
-        String testngJar = null;
-        for (String path : classPaths) {
-            if (path.endsWith("testng.jar")) {
-                testngJar = path;
-                break;
-            }
-        }
+        String testngJar = Path.of(Test.class.getProtectionDomain().getCodeSource().getLocation().toURI()).toString();
 
         String[] testClassNames = { "CustomFJPoolTest" };