faaf1cb5b9 util: Replace i64tostr with ToString (MarcoFalke)
fac96fff62 util: Remove unused itostr (MarcoFalke)
Pull request description:
Currently unused, but if someone really needed to use a helper with this functionality in the future, they could use `ToString`.
ACKs for top commit:
laanwj:
ACK faaf1cb5b9
promag:
Code review ACK faaf1cb5b9.
Tree-SHA512: 42180c03f51d677f7b69da23c7868bdd88944335fad0752fcc307f2c3e3c69f1cc1b316ac0875bcefb9a69c5d55200d7cf66843ea4c0f0f26baf7a054b96c1bb