Delete old assembleInterface code

Was breaking Google3 roll

if https://skia.googlesource.com/skia.git/+/93b3dce89d0cada44fd619571d55a1c83b751f70
is reverted, this should also be reverted

Change-Id: Ic065d89a8a06f1752644e7b8453f50ae3934f68c
Bug: skia:8474
NOTRY: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/203386
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Stan Iliev <stani@google.com>