Remove unneeded scripts for d8, r8-compat-proguard and retrace. am: 67a7974261 am: 6e2607fe3f am: c77c4e3288

Original change: https://android-review.googlesource.com/c/platform/prebuilts/r8/+/2056145

Change-Id: I42dbdbd0cef99de014b973132e3da6262f137266
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>