runtime: SIGSEGV in race + coverage mode [1.20 backport]

[gopherbot]

@prattmic requested issue #60825 to be considered for backport to the next 1.20 minor release.

@gopherbot Please open backports for 1.19 and 1.20. This bug can cause crashes on seemingly arbitrary atomic operations in race mode.

[gopherbot]

Change https://go.dev/cl/503976 mentions this issue: [release-branch.go1.20] runtime: use 1-byte load for address checking in racecallatomic

[gopherbot]

Closed by merging be30960 to release-branch.go1.20.