test: support candidate V8 versions

When V8 is built from its master branch, it adds a " (candidate)"
suffix to the version string. Add support for that in the tests so it
does not fail with Node canary.

PR-URL: #13282
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>

test/parallel/test-process-versions.js

@@ -26,5 +26,5 @@ assert(/^\d+\.\d+\.\d+(-.*)?$/.test(process.versions.http_parser));
 assert(/^\d+\.\d+\.\d+(-.*)?$/.test(process.versions.node));
 assert(/^\d+\.\d+\.\d+(-.*)?$/.test(process.versions.uv));
 assert(/^\d+\.\d+\.\d+(-.*)?$/.test(process.versions.zlib));
-assert(/^\d+\.\d+\.\d+(\.\d+)?$/.test(process.versions.v8));
+assert(/^\d+\.\d+\.\d+(\.\d+)?( \(candidate\))?$/.test(process.versions.v8));
 assert(/^\d+$/.test(process.versions.modules));