Upgrade robolectric to /external/robolectric to prep for removal of /external/robolectric shadows. am: 9e34a097be am: 777a476b26

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/KeyChain/+/21778940

Change-Id: I5ba04fcc7b592cbeac2cd75f1366ea6a4896bc1c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>