8055275: Several gc/class_unloading/ tests fail due to missed +UnlockDiagnosticVMOptions flag

Reviewed-by: mgerdin, jwilhelm
diff --git a/hotspot/test/gc/class_unloading/TestCMSClassUnloadingEnabledHWM.java b/hotspot/test/gc/class_unloading/TestCMSClassUnloadingEnabledHWM.java
index 5084079..906ac0f 100644
--- a/hotspot/test/gc/class_unloading/TestCMSClassUnloadingEnabledHWM.java
+++ b/hotspot/test/gc/class_unloading/TestCMSClassUnloadingEnabledHWM.java
@@ -45,6 +45,7 @@
   private static OutputAnalyzer run(boolean enableUnloading) throws Exception {
     ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
       "-Xbootclasspath/a:.",
+      "-XX:+UnlockDiagnosticVMOptions",
       "-XX:+WhiteBoxAPI",
       "-XX:MetaspaceSize=" + MetaspaceSize,
       "-Xmn" + YoungGenSize,
diff --git a/hotspot/test/gc/class_unloading/TestG1ClassUnloadingHWM.java b/hotspot/test/gc/class_unloading/TestG1ClassUnloadingHWM.java
index 66142a1..f4c830a 100644
--- a/hotspot/test/gc/class_unloading/TestG1ClassUnloadingHWM.java
+++ b/hotspot/test/gc/class_unloading/TestG1ClassUnloadingHWM.java
@@ -45,6 +45,7 @@
   private static OutputAnalyzer run(boolean enableUnloading) throws Exception {
     ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
       "-Xbootclasspath/a:.",
+      "-XX:+UnlockDiagnosticVMOptions",
       "-XX:+WhiteBoxAPI",
       "-XX:MetaspaceSize=" + MetaspaceSize,
       "-Xmn" + YoungGenSize,