Set USE_JACK to true.

This fixes running checker when just doing art/test/run-test.

Change-Id: Icfac5896cdfd64eb16b0127d5f16f552b93ad03e
diff --git a/test/run-test b/test/run-test
index d0f93b9..6bb1549 100755
--- a/test/run-test
+++ b/test/run-test
@@ -45,7 +45,7 @@
 export RUN="${progdir}/etc/run-test-jar"
 export DEX_LOCATION=/data/run-test/${test_dir}
 export NEED_DEX="true"
-export USE_JACK="false"
+export USE_JACK="true"
 export SMALI_ARGS="--experimental --api-level 23"
 
 # If dx was not set by the environment variable, assume it is in the path.
@@ -73,11 +73,6 @@
   export JACK="jack"
 fi
 
-# If the tree is compiled with Jack, build test with Jack by default.
-if [ "$ANDROID_COMPILE_WITH_JACK" = "true" ]; then
-  USE_JACK="true"
-fi
-
 # ANDROID_BUILD_TOP is not set in a build environment.
 if [ -z "$ANDROID_BUILD_TOP" ]; then
     export ANDROID_BUILD_TOP=$oldwd