Produce mappings of hashes to elf symbols and r8 dictionaries

Run the symbols_map tool on each unstripped binary and proguard
dictionary while copying it to produce a textproto that maps the
hash to the symbol/dictionary file location.  Combine the textprotos
into a mapping file when producing the zipped build artifacts.

Bug: 218888599
Test: m dist
Change-Id: I78997e2f3b631ed74213903cc8e72415b2d7eee0