runtime: deterministic fallback hashes across process boundary [1.22 backport]

[gopherbot]

@prattmic requested issue #66885 to be considered for backport to the next 1.22 minor release.

@gopherbot Please backport to 1.22. This regression makes map hashes deterministic across processes.

[gopherbot]

Change https://go.dev/cl/580018 mentions this issue: [release-branch.go1.22] runtime: use bootstrapRand to initialize hashkey

[gopherbot]

Closed by merging 3f4af1f to release-branch.go1.22.