runtime: doAllThreadsSyscall has an unaligned atomic load on 32-bit architectures [1.18 backport]

[gopherbot]

@prattmic requested issue #51776 to be considered for backport to the next 1.18 minor release.

Fixed in https://go.dev/cl/399754.

@gopherbot Please backport to 1.18. This is a regression with no workaround.

[gopherbot]

Change https://go.dev/cl/399954 mentions this issue: runtime: align m.procid to 8 bytes on 32-bit systems

[gopherbot]

Change https://go.dev/cl/399954 mentions this issue: [release-branch.go1.18] runtime: align m.procid to 8 bytes on 32-bit systems

[gopherbot]

Change https://go.dev/cl/399955 mentions this issue: [release-branch.go1.18] runtime: align m.procid to 8 bytes on 32-bit systems

[gopherbot]

Closed by merging 4f45424 to release-branch.go1.18.