Settings: Delete obsolete cr_settings_v3_browsertest.js file.

This file was originally deleted at [1], and then accidentally
re-introduced in a bad merge at [2]. Also restoring
CrSettingsLanguagesSubpageDetailedV3Test.NeverTranslateDialog tests
which were not actually executed as a result of the bad merge.

[1] https://chromium-review.googlesource.com/c/chromium/src/+/2823471
[2] https://chromium-review.googlesource.com/c/chromium/src/+/2816195

Bug: 1184052
Change-Id: I7ba492e0735a219a12c66857fb36c2f426ee1391
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2867245
Commit-Queue: John Lee <johntlee@chromium.org>
Auto-Submit: dpapad <dpapad@chromium.org>
Reviewed-by: John Lee <johntlee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#878509}

chrome/test/data/webui/settings/cr_settings_browsertest.js

@@ -148,6 +148,13 @@ TEST_F(
           .grep(languages_subpage_details_tests.TestNames.AlwaysTranslateDialog)
           .run();
     });
+
+TEST_F(
+    'CrSettingsLanguagesSubpageDetailedV3Test', 'NeverTranslateDialog',
+    function() {
+      mocha.grep(languages_subpage_details_tests.TestNames.NeverTranslateDialog)
+          .run();
+    });
 GEN('#endif');
 
 // eslint-disable-next-line no-var