okhttp.jar is needed by run-libcore-tests.

Some of the libcore's tests indirectly depend on okhttp being in the
CLASSPATH.

Change-Id: Iff5b7f361d088a08c31e7fcdea3ef243f4a2fe44
diff --git a/run-libcore-tests b/run-libcore-tests
index ef30877..fa5a33c 100755
--- a/run-libcore-tests
+++ b/run-libcore-tests
@@ -24,5 +24,6 @@
   --classpath out/target/common/obj/JAVA_LIBRARIES/core-tests_intermediates/javalib.jar \
   --classpath out/target/common/obj/JAVA_LIBRARIES/sqlite-jdbc_intermediates/classes.jar \
   --classpath out/target/common/obj/JAVA_LIBRARIES/bouncycastle_intermediates/classes.jar \
+  --classpath out/target/common/obj/JAVA_LIBRARIES/okhttp_intermediates/classes.jar \
   $test_packages \
   || true