internal/bisect: replace atomicPointerDedup to simplify the code
"atomicPointerDedup" is a redundancy of "atomic.Pointer".
Since Go 1.22 now requires the final point release of Go 1.20 or
later for bootstrap, Go 1.19's atomic.Pointer can be used
without problems.
atomicPointerDedup is unnecessary and we can remove it now.
Change-Id: I0a65ad0b6649cecb73d58dc39c5fd736390d5fa5
GitHub-Last-Rev:
6c6e9421fbdf34c2d4b3ea21359f847ccf9a34cd
GitHub-Pull-Request: golang/go#65987
Reviewed-on: https://go-review.googlesource.com/c/go/+/567656
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>