Revert "resolve: Unload speculatively resolved crates before freezing…

[weiznich]

… cstore"

This reverts commit a2ab48c.

Fixes #120830 by reverting the commit that introduced the regression.

cc @petrochenkov

[rustbot]

r? @pnkfelix

rustbot has assigned @pnkfelix.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[petrochenkov]

I haven't seen #120830.
We should rather fix it than revert #119592, I'll look at it tomorrow.

[petrochenkov]

CrateNum of the unloaded crate is preserved in SourceFile loaded at some point, then we attempt to access the unloaded crate data from EncodedSourceFileId::new if incremental compilation is enabled.

In OnDiskCache::serialize we go through all tcx.sess.source_map().files() and process them possibly accessing their corresponding crate data.

SourceFile is created when any span from the speculatively loaded crate is accessed (that means always?).

[petrochenkov]

Superseded by #121167.