gn2bp: Add JniRegistrationGenerator get_cmd am: 291f567f86

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2325458

Change-Id: I7339b1dfe8af33c4838ac2b8b59ca74f8b29165f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>