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/test/Android.bp b/test/Android.bp
index 287df13..1070645 100644
--- a/test/Android.bp
+++ b/test/Android.bp
@@ -272,6 +272,7 @@
         "929-search/search.cc",
         "931-agent-thread/agent_thread.cc",
         "933-misc-events/misc_events.cc",
+        "936-search-onload/search_onload.cc",
     ],
     shared_libs: [
         "libbase",