Only copy required folders for testing

After the task UI is migrated to polymer, it started generating
node_modules dir which is large and taking a lot of time to copy into
the container during the initialization of testing framework. So as to
overcome it, only copy required dirs.

Change-Id: I14f58dbf2654211aa727aacf86af6264c0a63e6e

test/docker/run_tests/start.sh

diff --git a/test/docker/run_tests/start.sh b/test/docker/run_tests/start.sh
index ac185d8..dd2cb63 100755
--- a/test/docker/run_tests/start.sh
+++ b/test/docker/run_tests/start.sh
@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 
 USER_RUN_TESTS_DIR="$USER_HOME"/"$RUN_TESTS_DIR"
-cp -r /task "$USER_HOME"/
+mkdir "$USER_HOME"/task && cp -r /task/{src,test} "$USER_HOME"/task
 
 if [ "$1" = "retest" ] ; then
     cd "$USER_RUN_TESTS_DIR"/../../ && ./check_task_statuses.sh "$GERRIT_HOST"