cmd/go: rewrite hgrepo1 test repo to be deterministic

cmd/go: rewrite hgrepo1 test repo to be deterministic

The use of git convert made it non-determinstic.
Build it up by hand using hg commands instead.

Change-Id: Iaa9c0925864a7003ea61e5bf2a9196ff3e0a662b
Reviewed-on: https://go-review.googlesource.com/c/go/+/718520
Auto-Submit: Russ Cox <rsc@golang.org>
Reviewed-by: Michael Matloob <matloob@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Matloob <matloob@golang.org>