Fix meridian tests failing around TZ offset issues.

When local time and UTC are in different halves of the meridian tests
would fail as the new changes in DateTimeWidget would default the
meridian to pm.

src/View/Helper/FormHelper.php

@@ -2075,9 +2075,11 @@ class FormHelper extends Helper
         $options = $this->_singleDatetime($options, 'meridian');
 
         if (isset($options['val'])) {
+            $hour = date('H');
             $options['val'] = [
-                'hour' => date('H'),
+                'hour' => $hour,
                 'minute' => (int)$options['val'],
+                'meridian' => $hour > 11 ? 'pm' : 'am',
             ];
         }
         return $this->datetime($fieldName, $options);

tests/TestCase/View/Helper/FormHelperTest.php

@@ -5355,15 +5355,15 @@ class FormHelperTest extends TestCase
     {
         extract($this->dateRegex);
 
-        $now = time();
+        $now = new \DateTime();
         $result = $this->Form->meridian('Model.field', ['value' => 'am']);
         $expected = [
             ['select' => ['name' => 'Model[field][meridian]']],
             ['option' => ['value' => '']],
             '/option',
             $meridianRegex,
-            ['option' => ['value' => date('a', $now), 'selected' => 'selected']],
-            date('a', $now),
+            ['option' => ['value' => $now->format('a'), 'selected' => 'selected']],
+            $now->format('a'),
             '/option',
             '*/select'
         ];