Fix to work in VS Code context

it avoids to rely on `process.execPath` which resolves to `code` binary
in VS Code context although it expects the `node` binary

relates to asciidoctor/asciidoctor-vscode#731

Signed-off-by: Aurélien Pupier <apupier@redhat.com>

lib/XMLHttpRequest.js

@@ -517,10 +517,9 @@ exports.XMLHttpRequest = function () {
  : DEFAULT_MAX_BUFFER
  const encoding = responseType === 'text' ? 'utf8' : 'binary'
  const scriptPath = ospath.join(__dirname, 'request.js')
- const output = require('child_process').execSync(`"${process.execPath}" "${scriptPath}" \
---ssl="${ssl}" \
---encoding="${encoding}" \
---request-options=${JSON.stringify(JSON.stringify(options))}`, { stdio: ['pipe', 'pipe', 'pipe'], input: data, maxBuffer: maxBuffer })
+ const output = require('child_process').execFileSync(scriptPath,
+ [`--ssl="${ssl}"`, `--encoding="${encoding}"`, `--request-options=${JSON.stringify(JSON.stringify(options))}`],
+ { stdio: ['pipe', 'pipe', 'pipe'], input: data, maxBuffer: maxBuffer })
  const result = JSON.parse(output.toString('utf8'))
  if (result.error) {
  throw translateError(result.error, url)