Removed log line from AMP parsing

refs https://github.com/TryGhost/Ghost/pull/9097

- this was originally added to measure the AMP parsing time but AMP is
  becoming less and less important (it's disabled by default in Ghost
  now)
- this also causes a lot of noise when viewing logs, and I've never
  experienced an issue with AMP parsing time that we've needed to review
  these logs
- therefore, this commit deletes it

ghost/core/core/frontend/apps/amp/lib/helpers/amp_content.js

@@ -6,7 +6,7 @@
 //
 // Converts normal HTML into AMP HTML with Amperize module and uses a cache to return it from
 // there if available. The cacheId is a combination of `updated_at` and the `slug`.
-const {DateTime, Interval} = require('luxon');
+const {DateTime} = require('luxon');
 const errors = require('@tryghost/errors');
 const logging = require('@tryghost/logging');
 
@@ -120,8 +120,6 @@ function getAmperizeHTML(html, post) {
 
     amperize = amperize || new Amperize();
 
-    const startedAtMoment = DateTime.now();
-
     let cacheDateTime;
     let postDateTime;
 
@@ -136,8 +134,6 @@ function getAmperizeHTML(html, post) {
     if (!amperizeCache[post.id] || cacheDateTime.diff(postDateTime).valueOf() < 0) {
         return new Promise((resolve) => {
             amperize.parse(html, (err, res) => {
-                logging.info('amp.parse', post.url, Interval.fromDateTimes(startedAtMoment, DateTime.now()).length('milliseconds') + 'ms');
-
                 if (err) {
                     if (err.src) {
                         // This is a valid 500 GhostError because it means the amperize parser is unable to handle some Ghost HTML.