8237223: Shenandoah: important flags should not be ergonomic for concurrent class unloading

Reviewed-by: zgu

Author: shipilev

src/hotspot/share/gc/shenandoah/shenandoahNormalMode.cpp

@@ -33,13 +33,14 @@
 #include "logging/logTag.hpp"
 
 void ShenandoahNormalMode::initialize_flags() const {
-  SHENANDOAH_ERGO_ENABLE_FLAG(ExplicitGCInvokesConcurrent);
-  SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahImplicitGCInvokesConcurrent);
   if (ShenandoahConcurrentRoots::can_do_concurrent_class_unloading()) {
-    SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahSuspendibleWorkers);
-    SHENANDOAH_ERGO_DISABLE_FLAG(VerifyBeforeExit);
+    FLAG_SET_DEFAULT(ShenandoahSuspendibleWorkers, true);
+    FLAG_SET_DEFAULT(VerifyBeforeExit, false);
   }
 
+  SHENANDOAH_ERGO_ENABLE_FLAG(ExplicitGCInvokesConcurrent);
+  SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahImplicitGCInvokesConcurrent);
+
   // Final configuration checks
   SHENANDOAH_CHECK_FLAG_SET(ShenandoahLoadRefBarrier);
   SHENANDOAH_CHECK_FLAG_SET(ShenandoahSATBBarrier);