database/sql: do not store Tx options in Context

Drivers which previously supported tip will need to update to this
revision before release.

Fixes #18284

Change-Id: I70b8e7afff1558a8b5348885ce9f50e067c72ee9
Reviewed-on: https://go-review.googlesource.com/34330
Run-TryBot: Daniel Theophanes <kardianos@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/database/sql/sql_test.go b/src/database/sql/sql_test.go
index 1ec6217..422d219 100644
--- a/src/database/sql/sql_test.go
+++ b/src/database/sql/sql_test.go
@@ -375,7 +375,7 @@
 
 	ctx, _ := context.WithTimeout(context.Background(), time.Millisecond*15)
 
-	tx, err := db.BeginContext(ctx)
+	tx, err := db.BeginTx(ctx, nil)
 	if err != nil {
 		t.Fatal(err)
 	}