repl: editor mode text not saved in `.save` command

[jcpst]

• Version: 6.4.0
• Platform: Linux arch 4.7.0-1-ARCH #1 SMP PREEMPT Mon Aug 8 22:05:58 CEST 2016 x86_64 GNU/Linux
• Subsystem: repl

The new editor mode is wonderful, but I'm unable to to save what was done in the editor mode using the .save command.

> const foo = 1
undefined
> const bar = 'two'
undefined
> .editor
// Entering editor mode (^D to finish, ^C to cancel)
function fooey () {
  return 'fooey'
}
undefined
> fooey()
'fooey'
> .save zzz.js
Session saved to:zzz.js

zzz.js:

const foo = 1
const bar = 'two'

fooey()

[addaleax]

/cc @princejwesley

[princejwesley]

@addaleax I'll share the fix shortly