Emit unique linker buildid in all binaries.

We want to store the symbol information for all android binaries in a global database.

* We ingest unstripped binaries into the global database
* When we collect address data from device (e.g. instruction pointer address), we want to lookup its symbol information through the global database. The key of the mapping is a unique build id, which is the same between binaries on device (stripped) and unstripped binaries.

After applying this patch, the system.img size increases by 0.0047% (16.3KB).

Change-Id: Id92faf2951f43a30947e8d2b690c1af6bf7e3f54