--light is noisy

[amaury1093]

Either running ./target/release/polkadot --light from the polkadot repo, or here ./target/release substrate --light, I get a lot of:

2020-05-11 17:28:59 Failed to fetch block body: RemoteFetchCancelled
...
2020-05-11 17:28:59 Couldn't start light client request: too many pending requests
...
2020-05-11 17:29:14 Failed to fetch block body: RemoteFetchFailed
...
2020-05-11 17:27:44 Couldn't start light client request: too many pending requests

Here's a gist: https://gist.github.com/amaurymartiny/f378da1f7620e6074a48048753e2d3e4

Are all those remote requests needed?

cc @svyatonik maybe?