Fix default cdex level to be fast instead of none

To get treehugger running the tests for presubmits.

Bug: 63756964
Test: manual
Change-Id: Ie233b673cb7357b928dc2102bc6d30a66f2e009f
diff --git a/test/testrunner/target_config.py b/test/testrunner/target_config.py
index 2bb407d..414e3e5 100644
--- a/test/testrunner/target_config.py
+++ b/test/testrunner/target_config.py
@@ -230,7 +230,7 @@
     'art-heap-poisoning' : {
         'run-test' : ['--interpreter',
                       '--optimizing',
-                      '--cdex-fast'],
+                      '--cdex-none'],
         'env' : {
             'ART_USE_READ_BARRIER' : 'false',
             'ART_HEAP_POISONING' : 'true',
diff --git a/test/testrunner/testrunner.py b/test/testrunner/testrunner.py
index 9399857..8a1e06c 100755
--- a/test/testrunner/testrunner.py
+++ b/test/testrunner/testrunner.py
@@ -185,7 +185,7 @@
     _user_input_variants['prebuild'].add('prebuild')
 
   if not _user_input_variants['cdex_level']: # Default
-    _user_input_variants['cdex_level'].add('cdex-none')
+    _user_input_variants['cdex_level'].add('cdex-fast')
 
   # By default only run without jvmti
   if not _user_input_variants['jvmti']: