Fix missing expectations in run-libcore-tests.sh

Test: art/tools/run-libcore-tests.sh --mode=host -- libcore.libcore.net
Change-Id: I2aacb7a67ab0e04ae8a55bd839ed16f4604c1423
diff --git a/tools/run-libcore-tests.sh b/tools/run-libcore-tests.sh
index 3b8d32a..a6c1b14 100755
--- a/tools/run-libcore-tests.sh
+++ b/tools/run-libcore-tests.sh
@@ -257,6 +257,9 @@
 fi  # $execution_mode = "device"
 
 if [ $execution_mode = "device" -o $execution_mode = "host" ]; then
+  # Use default expectations
+  expectations="--expectations art/tools/libcore_failures.txt"
+
   # set the toolchain to use.
   vogar_args="$vogar_args --toolchain d8 --language CUR"