MM-10020: avoid duplicating unique indexes (#8587)

* unit test TestGet(Search)Replica

This adds partial, testing-focused support for SQLite, as well as removing
some translated log messages that required initializing i18n just for
testing.

* avoid returning master twice when no replicas are configured

* remove duplicate indexes

* unit test GetAllConns

vendor/github.com/mattn/go-sqlite3/sqlite3_go18.go

@@ -0,0 +1,69 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+// +build go1.8
+
+package sqlite3
+
+import (
+	"database/sql/driver"
+	"errors"
+
+	"context"
+)
+
+// Ping implement Pinger.
+func (c *SQLiteConn) Ping(ctx context.Context) error {
+	if c.db == nil {
+		return errors.New("Connection was closed")
+	}
+	return nil
+}
+
+// QueryContext implement QueryerContext.
+func (c *SQLiteConn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
+	list := make([]namedValue, len(args))
+	for i, nv := range args {
+		list[i] = namedValue(nv)
+	}
+	return c.query(ctx, query, list)
+}
+
+// ExecContext implement ExecerContext.
+func (c *SQLiteConn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
+	list := make([]namedValue, len(args))
+	for i, nv := range args {
+		list[i] = namedValue(nv)
+	}
+	return c.exec(ctx, query, list)
+}
+
+// PrepareContext implement ConnPrepareContext.
+func (c *SQLiteConn) PrepareContext(ctx context.Context, query string) (driver.Stmt, error) {
+	return c.prepare(ctx, query)
+}
+
+// BeginTx implement ConnBeginTx.
+func (c *SQLiteConn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
+	return c.begin(ctx)
+}
+
+// QueryContext implement QueryerContext.
+func (s *SQLiteStmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
+	list := make([]namedValue, len(args))
+	for i, nv := range args {
+		list[i] = namedValue(nv)
+	}
+	return s.query(ctx, list)
+}
+
+// ExecContext implement ExecerContext.
+func (s *SQLiteStmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error) {
+	list := make([]namedValue, len(args))
+	for i, nv := range args {
+		list[i] = namedValue(nv)
+	}
+	return s.exec(ctx, list)
+}