cmd/link/internal/arm: off-by-one error in trampoline phase call reachability calculation [1.20 backport]

[gopherbot]

@thanm requested issue #59034 to be considered for backport to the next 1.20 minor release.

@gopherbot please open backport issues

[gopherbot]

Change https://go.dev/cl/476936 mentions this issue: [release-branch.go1.20] cmd/link/internal/arm: fix off-by-1 in trampoline reachability computation

[gopherbot]

Closed by merging b52a696 to release-branch.go1.20.