repl: unflag Top-Level Await
Now that we have #34558 it makes sense to unflag Top-Level await for the REPL?
This PR is getting rid of --experimental-repl-await
flag and the checks related to the same.
❯ node
Welcome to Node.js v14.8.0.
Type ".help" for more information.
> process.version
'v14.8.0'
> await Promise.resolve(123)
await Promise.resolve(42)
^^^^^
Uncaught SyntaxError: await is only valid in async function
❯ ./node
Welcome to Node.js v15.0.0-pre.
Type ".help" for more information.
> await Promise.resolve(42)
42