Rollup merge of #149916 - zetanumbers:double_node_sanity, r=petrochenkov

Add a sanity check in case of any duplicate nodes

A simple check in case compiler tries to encode a dep node twice like in rust-lang/rust#141540.

Also if we'd try to mark a red node as green as it may then create a bad `DepNodeIndex` like in rust-lang/rust#148295.

If it prevents rust-lang/rust#141540 from emitting a faulty `dep-graph.bin` file via panic then it means you will be able to temporarily fix it by simply restarting cargo or rust-analyzer without cleaning up incremental cache.

Author: jhpratt