Add platform-mainline-test-exports in list of modules to build.

Needed for ART testing.

Bug: 142935992
Test: build-mainline-modules.sh

Change-Id: I842feff85f88ecc2c7db1e84e803d9e8149923af
diff --git a/scripts/build-mainline-modules.sh b/scripts/build-mainline-modules.sh
index c7baca7..c5ec8d1 100755
--- a/scripts/build-mainline-modules.sh
+++ b/scripts/build-mainline-modules.sh
@@ -24,6 +24,7 @@
   i18n-module-test-exports
   i18n-module-sdk
   platform-mainline-sdk
+  platform-mainline-test-exports
 )
 
 # List of libraries installed on the platform that are needed for ART chroot