internal/ethapi: remove td field from block

[s1na]

Implements ethereum/execution-apis#570

[s1na]

If we remove GetTd usage from ethstats then the method could be dropped from the EthAPIBackend completely.

[rjl493456442]

If we remove GetTd usage from ethstats

Why not?

EDIT: Okay, let's keep it for a while, not sure whether ethstats will fail or not without the TD (although
they communicate via JSON)

[holiman]

LGTM

[lightclient]

Looks like there are still some references to "totalDifficulty" in a few places that should also be cleaned up:

• eth/tracers/internal/tracetest/testdata/
• internal/jsre/deps/web3.js
• ethstats

[s1na]

Looks like there are still some references to "totalDifficulty" in a few places

Yep I fixed the ones in eth/tracers/internal/tracetest. Those were filled via API and had those fields. The totalDifficulty was also unused even before this because it decodes into *core.Genesis.

internal/jsre/deps/web3.js

Hm this one makes it so that when I do eth.getBlock in the console it shows "totalDifficulty": 0. Which is confusing. I am mindful that this is an external dependency and we shouldn't change it often. But since we haven't really updated web3.js or plan to do that I will go ahead and remove the offending line.

ethstats

I'd like to keep this out of this PR.

[s1na]

Fixed last standing issue. PTAL