*/*: update NGINX JavaScript: 0.8.7 -> 0.8.8 (+)

Bump PORTREVISION for the www/unit.

<ChangeLog>

nginx modules:

*) Feature: implemented shared dictionary for QuickJS engine.

*) Improvement: js_preload_object is refactored.

*) Bugfix: fixed limit rated output.

*) Bugfix: optimized use of SSL contexts for
   js_fetch_trusted_certificate directive.

Core:

*) Feature: implemented process object for QuickJS engine.

*) Feature: implemented process.kill() method.

*) Bugfix: fixed tests with libxml2 2.13 and later.

*) Bugfix: fixed promise resolving when Promise is inherited.

*) Bugfix: fixed absolute scope in cloned VMs.

</ChangeLog>