cmd/go/internal/vcs: include Subversion VCS build information
The existing implementation lacks the Status function for retrieving VCS build
information for Subversion. As a consequence, binaries aren't stamped with the
Revision, CommitTime and Uncommitted information from SVN repositories.
This change provides the svnStatus function and retrieves the information by
running svn info and svn status commands.
Fixes #73444
Change-Id: Ie6d95ffbb3a3c580cc42128ad1f8d82a869c91f2
GitHub-Last-Rev:
3472222865638a13b122c8995561166cfe228fa8
GitHub-Pull-Request: golang/go#73446
Reviewed-on: https://go-review.googlesource.com/c/go/+/666875
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Sean Liao <sean@liao.dev>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Sam Thanawalla <samthanawalla@google.com>