ScanType() should not return sql.RawBytes

[methane]

Issue description

When I investing #1390, I found XORM used sql.RawBytes for ScanType. It was XORM bug.
But we have same bug!

mysql/fields.go

Lines 190 to 195 in cffc85c

	case fieldTypeDecimal, fieldTypeNewDecimal, fieldTypeVarChar,
	fieldTypeBit, fieldTypeEnum, fieldTypeSet, fieldTypeTinyBLOB,
	fieldTypeMediumBLOB, fieldTypeLongBLOB, fieldTypeBLOB,
	fieldTypeVarString, fieldTypeString, fieldTypeGeometry, fieldTypeJSON,
	fieldTypeTime:
	return scanTypeRawBytes

Example code

https://github.com/methane/notes/blob/master/2023/go-mysql-race/main.go

Error log

$ go run -race .
Hello, 0 Hello, 0 Hello, 0 Hello, 0 Hello, 0
==================
WARNING: DATA RACE
Read at 0x00c000166040 by goroutine 8:
  runtime.slicebytetostring()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/runtime/string.go:81 +0x0
  main.main.func1()
      /Users/inada-n/notes/2023/go-mysql-race/main.go:46 +0x64
  main.main.func3()
      /Users/inada-n/notes/2023/go-mysql-race/main.go:52 +0x78

Previous write at 0x00c000166040 by main goroutine:
  runtime.racewriterange()
      <autogenerated>:1 +0x14
  internal/poll.ignoringEINTRIO()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/internal/poll/fd_unix.go:794 +0x2ec
  internal/poll.(*FD).Read()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/internal/poll/fd_unix.go:163 +0x20
  net.(*netFD).Read()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/net/fd_posix.go:55 +0x44
  net.(*conn).Read()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/net/net.go:183 +0x84
  net.(*TCPConn).Read()
      <autogenerated>:1 +0x4c
  github.com/go-sql-driver/mysql.(*buffer).fill()
      /Users/inada-n/go/pkg/mod/github.com/go-sql-driver/mysql@v1.7.1/buffer.go:90 +0x33c
  github.com/go-sql-driver/mysql.(*buffer).readNext()
      /Users/inada-n/go/pkg/mod/github.com/go-sql-driver/mysql@v1.7.1/buffer.go:119 +0x54
  github.com/go-sql-driver/mysql.(*mysqlConn).readPacket()
      /Users/inada-n/go/pkg/mod/github.com/go-sql-driver/mysql@v1.7.1/packets.go:32 +0xa4
  github.com/go-sql-driver/mysql.(*mysqlStmt).readPrepareResultPacket()
      /Users/inada-n/go/pkg/mod/github.com/go-sql-driver/mysql@v1.7.1/packets.go:830 +0x38
  github.com/go-sql-driver/mysql.(*mysqlConn).Prepare()
      /Users/inada-n/go/pkg/mod/github.com/go-sql-driver/mysql@v1.7.1/connection.go:182 +0x2e8
  github.com/go-sql-driver/mysql.(*mysqlConn).PrepareContext()
      /Users/inada-n/go/pkg/mod/github.com/go-sql-driver/mysql@v1.7.1/connection.go:533 +0x58
  database/sql.ctxDriverPrepare()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/database/sql/ctxutil.go:15 +0x11c
  database/sql.(*DB).queryDC.func2()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/database/sql/sql.go:1770 +0x88
  database/sql.withLock()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/database/sql/sql.go:3405 +0x84
  database/sql.(*DB).queryDC()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/database/sql/sql.go:1769 +0x25c
  database/sql.(*DB).query()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/database/sql/sql.go:1726 +0xf0
  database/sql.(*DB).QueryContext.func1()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/database/sql/sql.go:1704 +0x9c
  database/sql.(*DB).retry()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/database/sql/sql.go:1538 +0x4c
  database/sql.(*DB).QueryContext()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/database/sql/sql.go:1703 +0xc8
  database/sql.(*DB).Query()
      /opt/homebrew/Cellar/go/1.20.3/libexec/src/database/sql/sql.go:1717 +0x144
  main.main()
      /Users/inada-n/notes/2023/go-mysql-race/main.go:28 +0xf0

Goroutine 8 (running) created at:
  main.main()
      /Users/inada-n/notes/2023/go-mysql-race/main.go:43 +0x180
==================

Configuration

Driver version (or git SHA):

Go version: run go version in your console

Server version: E.g. MySQL 5.6, MariaDB 10.0.20

Server OS: E.g. Debian 8.1 (Jessie), Windows 10