cmd/compile: tweak inliners handling of coverage counter updates
This patch fixes up a bug in the inliner's special case code for
coverage counter updates, which was not properly working for
-covermode=atomic compilations.
Updates #56044.
Change-Id: I9e309312b123121c3df02862623bdbab1f6c6a4b
Reviewed-on: https://go-review.googlesource.com/c/go/+/441858 Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Than McIntosh <thanm@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>