Auto merge of rust-lang#139625 - Zoxc:revert-pr138824, r=oli-obk

[beta] Revert "Remove `prev_index_to_index` field from `CurrentDepGraph`"

This reverts rust-lang#138824 on beta to fix issues with incremental compilation in that PR. rust-lang#139410 will fix these on master.

r? `@oli-obk`

Author: bors