ART: Add OnLoad system classloader search support

Add support for extension of the system classloader search path
during the OnLoad phase. Add test.

Bug: 34359699
Test: m test-art-host-run-test-936-search-onload
Change-Id: Ie0a5b4bb77999dfae87f955dde40b73ffe053b8e
diff --git a/runtime/openjdkjvmti/OpenjdkJvmTi.cc b/runtime/openjdkjvmti/OpenjdkJvmTi.cc
index c0c301f..a815a60 100644
--- a/runtime/openjdkjvmti/OpenjdkJvmTi.cc
+++ b/runtime/openjdkjvmti/OpenjdkJvmTi.cc
@@ -1368,6 +1368,7 @@
   ThreadUtil::Register(&gEventHandler);
   ClassUtil::Register(&gEventHandler);
   DumpUtil::Register(&gEventHandler);
+  SearchUtil::Register();
 
   runtime->GetJavaVM()->AddEnvironmentHook(GetEnvHandler);
   runtime->AddSystemWeakHolder(&gObjectTagTable);
@@ -1380,6 +1381,7 @@
   ThreadUtil::Unregister();
   ClassUtil::Unregister();
   DumpUtil::Unregister();
+  SearchUtil::Unregister();
 
   return true;
 }