Auto merge of #124256 - nnethercote:rm-NtIdent-NtLifetime, r=petrochenkov

Remove `NtIdent` and `NtLifetime`

This is one part of the bigger "remove `Nonterminal` and `TokenKind::Interpolated`" change drafted in #114647. More details in the individual commit messages.

r? `@petrochenkov`

Author: bors