iter: fix race instrumentation for Pull2
Pull2 tests are failing with -race, giving false-positive race conditions
due to bad race instrumentation.
No tests for this as it should be caught by the race builders. The only
reason it was not caught is because it is behind GOEXPERIMENT=rangefunc.
Fixes #64651
Change-Id: I20554da930b0e19594e0e267f01a1e7a9cbc577a
GitHub-Last-Rev:
7c1f19238d2c0b7efa5f0a2033893914e402bbc2
GitHub-Pull-Request: golang/go#64653
Reviewed-on: https://go-review.googlesource.com/c/go/+/548895
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>