Start building prebuilts for bpfmt and ckati_stamp_dump

* bpfmt for pre-upload checks to use
* ckati_stamp_dump for treehugger to read the kati stamp files

Since bpfmt is a go program, there's no point installing a second
version for ASAN.

Test: prebuilts/build-tools/build-prebuilts.sh
Change-Id: I1fbb1f302f878609ed99db091daed5cfa6a47f56