[Debuginfod] Add BUILD_ID syntax to llvm-symbolizer.

This adds a BUILD_ID prefix to the llvm-symbolizer stdin and argument
syntax. The prefix causes the given binary name to be interpreted as a
build ID instead of an object file path. The semantics are analagous to
the behavior of --obj and --build-id.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D119901