eth/tracers/live: run supply tests off of generated artifacts

[s1na]

I think the block test format used for consensus testing is also ideal for testing live tracers. I have taken our existing tests for the supply tracer and turned them into a filler binary + a dumb test runner that takes processes the json files. I believe this format can be re-used for other live tracers (with the exception of the "except" field which would be different).

The only thorn in my side is the filler. I've put it as an executable module right now in eth/tracers/live/tests.