Add kotlin presubmit hooks to platform_testing

Test: check if hooks are run on presubmit
Change-Id: Ic83dbd00981c8cfe5a3db0be2b74b0f73f98cc32
diff --git a/PREUPLOAD.cfg b/PREUPLOAD.cfg
index a74063e..0bfbc43 100644
--- a/PREUPLOAD.cfg
+++ b/PREUPLOAD.cfg
@@ -16,3 +16,4 @@
                       libraries/system-helpers
                       libraries/timeresult-helpers
 
+ktlint_hook = ${REPO_ROOT}/prebuilts/ktlint/ktlint.py -f ${PREUPLOAD_FILES}
\ No newline at end of file