setPGOProfilePath sets Package.Internal.PGOProfile very late in package
loading (because it may split/copy packages). Build info was computed
long before this, causing PGO packages to miss -pgo from their build
settings.
Adjust BuildInfo to be stored as *debug.BuildInfo rather than eagerly
converting to a string. This enables setPGOProfilePath to update the
BuildInfo at the same point that it sets PGOProfile.
Change-Id: Ic12266309bfd0f8ec440b0dc94d4df813b27cb04
Reviewed-on: https://go-review.googlesource.com/c/go/+/496958
Run-TryBot: Michael Pratt <mpratt@google.com> Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Michael Pratt <mpratt@google.com>