8357382: runtime/cds/appcds/aotClassLinking/BulkLoaderTest.java#aot fails with Xcomp and C1

Backport-of: 429158218b52964ad1e79ba9d2fa5618d6b3398e

Author: shipilev

test/hotspot/jtreg/runtime/cds/appcds/aotClassLinking/BulkLoaderTest.java

@@ -78,6 +78,7 @@
 import java.lang.StackWalker.StackFrame;
 import java.net.URL;
 import java.net.URLClassLoader;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -318,12 +319,15 @@ static void checkCustomLoader() throws Exception {
         }
     }
 
+    static ArrayList<ClassLoader> savedLoaders = new ArrayList<>();
+
     static Object initFromCustomLoader() throws Exception {
         String path = "cust.jar";
         URL url = new File(path).toURI().toURL();
         URL[] urls = new URL[] {url};
         URLClassLoader urlClassLoader =
             new URLClassLoader("MyLoader", urls, null);
+        savedLoaders.add(urlClassLoader);
         Class c = Class.forName("SimpleCusty", true, urlClassLoader);
         return c.newInstance();
     }