*/*: update NGINX JavaScript 0.7.7 -> 0.7.8

Bump PORTREVISION for www/nginx-devel.

<ChangeLog>

nginx modules:

*) Feature: added js_preload_object directive.

*) Feature: added ngx.conf_prefix property.

*) Feature: added s.sendUpstream() and s.sendDownstream()
   in stream module.

*) Feature: added support for HEAD method in Fetch API.

*) Improvement: improved async callback support for s.send()
   in stream module.

Core:

*) Feature: added "name" instance property for a function
   object.

*) Feature: added njs.memoryStats object.

*) Bugfix: fixed String.prototype.trimEnd() with unicode
   string.

*) Bugfix: fixed Object.freeze() with fast arrays.

*) Bugfix: fixed Object.defineProperty() with fast arrays.

*) Bugfix: fixed async token as a property name of an object.

*) Bugfix: fixed property set instruction when key modifies
   base binding.

*) Bugfix: fixed complex assignments.

*) Bugfix: fixed handling of unhandled promise rejection.

*) Bugfix: fixed process.env when duplicate environ variables
   are present.

*) Bugfix: fixed double declaration detection in modules.

*) Bugfix: fixed bound function calls according to the spec.

*) Bugfix: fixed break label for if statement.

*) Bugfix: fixed labeled empty statements.

</ChangeLog>