debugValue: handle Interfaces better. am: 89e90b4c60

Original change: https://android-review.googlesource.com/c/platform/build/blueprint/+/2975295

Change-Id: Iba23845605d8cdeb400f65cc3da34e4e2239b1d6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>