Disable stack guarding on the primordial thread because its protections
are immutable. Note this will interfere with the primordial thread throwing
StackOverflowError exceptions.

Index: src/hotspot/share/runtime/thread.cpp
--- src/hotspot/share/runtime/thread.cpp.orig
+++ src/hotspot/share/runtime/thread.cpp
@@ -2608,7 +2608,11 @@ size_t JavaThread::_stack_shadow_zone_size = 0;
 void JavaThread::create_stack_guard_pages() {
   if (!os::uses_stack_guard_pages() ||
       _stack_guard_state != stack_guard_unused ||
+#ifdef __OpenBSD__
+      (os::is_primordial_thread())) {
+#else
       (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
+#endif
       log_info(os, thread)("Stack guard page creation for thread "
                            UINTX_FORMAT " disabled", os::current_thread_id());
     return;
