cmd/go: fix test for issue 8181

The test was translated from shell incorrectly,
and it depended on having hg installed, which
may not be the case.

Moved repo to GitHub, updated code, and fixed
go list ... command to be expected to succeed.

Fixes test for #8181.

Change-Id: I7f3e8fb20cd16cac5ed24de6fd952003bc5e08d4
Reviewed-on: https://go-review.googlesource.com/11301Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/go/go_test.go

@@ -1403,9 +1403,9 @@ func TestGoGetDashTIssue8181(t *testing.T) {
 	tg.parallel()
 	tg.makeTempdir()
 	tg.setenv("GOPATH", tg.path("."))
-	tg.run("get", "-t", "code.google.com/p/go-get-issue-8181/a", "code.google.com/p/go-get-issue-8181/b")
-	tg.runFail("list", "...")
-	tg.grepStdout("go.tools/godoc", "missing expected go.tools/godoc")
+	tg.run("get", "-v", "-t", "github.com/rsc/go-get-issue-8181/a", "github.com/rsc/go-get-issue-8181/b")
+	tg.run("list", "...")
+	tg.grepStdout("x/build/cmd/cl", "missing expected x/build/cmd/cl")
 }
 
 func TestShadowingLogic(t *testing.T) {