debugger: --debug-brk should pause until debug client connects

[bnoordhuis]

See #3585 (comment). Right now it quits:

$ node --debug-brk -e 0
Debugger listening on port 5858
$

I think the intended behavior is for it to wait until a debug client connects, unlike e.g. --debug.

[bnoordhuis]

/cc @indutny

[Trott]

It appears that, as it is currently written,test/parallel/test-debug-brk.js depends on this bug. If it were not for this bug, that test would not exit:

'use strict';

const common = require('../common');
const assert = require('assert');
const spawnSync = require('child_process').spawnSync;

const args = [`--debug-brk=${common.PORT}`, '-e', '0'];
const proc = spawnSync(process.execPath, args, {encoding: 'utf8'});
assert(/Debugger listening on/.test(proc.stderr));

[bnoordhuis]

I added test/parallel/test-debug-brk.js in #3585 to catch regressions in the current behavior. I don't think the current behavior is the best or the intended behavior, though.

[Trott]

Possible fix: #7089