Remove obsolete quickening-related TODO comments. am: 79f9e3647b

Original change: https://android-review.googlesource.com/c/platform/art/+/2984732

Change-Id: I19300c983c72cde119fb7f1dc7a9090e122771c9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>