ART: Re-enable TI tests for target

Fix invalid null handle for dlsym on arm32. Fix missing cast in
dispatch.

Remove the test black-list.

Bug: 31681198
Test: m test-art-target-run-test (bullhead)
Change-Id: I3edc68421933330b4361fb9e49d4e5ff4966a4ff
diff --git a/test/ti-agent/common_helper.cc b/test/ti-agent/common_helper.cc
index fd9fc38..80e1797 100644
--- a/test/ti-agent/common_helper.cc
+++ b/test/ti-agent/common_helper.cc
@@ -349,7 +349,7 @@
     names[1] = m->JniLongName();
   }
   for (const std::string& mangled_name : names) {
-    void* sym = dlsym(nullptr, mangled_name.c_str());
+    void* sym = dlsym(RTLD_DEFAULT, mangled_name.c_str());
     if (sym == nullptr) {
       continue;
     }