The dependency was due to the log format. This change switches to the
previously-introduced (D139370) "dependency-free" logger instead of the
protobuf-based one.
A subsequent change will clean out the unnecessary abstraction left
behind.
This change drops the logger unittest, we have sufficient test coverage
via lit tests, and a unit test would require adding, unnecesarily, a log
reader (the reader is expected to be python, for the ML side, and there
is a reader for that under Analysis/models, used for tests).
Maybe note here explicitly we're regexing most of the opcodes due to exact values causing test failures over minor differences? Otherwise the regex might be somewhat hard to parse without additional context.