Unexpire MaxAutocompleteMatches feature flag.

Change-Id: I8c25d4aa54853d67017d04e9e03c0cf955902a0c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2301179
Commit-Queue: Ender <ender@google.com>
Commit-Queue: Ted Choc <tedchoc@chromium.org>
Auto-Submit: Ender <ender@google.com>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#788879}

chrome/browser/flag-metadata.json

@@ -3285,7 +3285,7 @@
   {
     "name": "omnibox-ui-max-autocomplete-matches",
     "owners": [ "jdonnelly", "chrome-omnibox-team@google.com" ],
-    "expiry_milestone": 85
+    "expiry_milestone": 95
   },
   {
     "name": "omnibox-ui-reveal-steady-state-url-path-query-and-ref-on-hover",