Add art-ndebug target to target_config.py

Test: manual
Change-Id: I0040e30e95f5fc49190d191a2cbf329f09de668a
diff --git a/test/testrunner/target_config.py b/test/testrunner/target_config.py
index 97d4509..474c259 100644
--- a/test/testrunner/target_config.py
+++ b/test/testrunner/target_config.py
@@ -42,6 +42,12 @@
     # ART run-test configurations
     # (calls testrunner which builds and then runs the test targets)
 
+    'art-ndebug' : {
+        'run-test' : ['--ndebug'],
+        'env' : {
+            'ART_USE_READ_BARRIER' : 'true'
+        }
+    },
     'art-interpreter' : {
         'run-test' : ['--interpreter'],
         'env' : {