Merge branch '5.2' into 5.x

* 5.2:
  Fix EncoderInterface::encode() return type
  [Lock] Prevent store exception break combined store
  Remove check for unsupported PHP version
  [Notifier] Rename test method names
  Fix missing kernel.build_dir on cache clear
  [Notifier][Discord] Fix exception message + test

Author: nicolas-grekas

Tests/DateFormatter/Verification/IntlDateFormatterTest.php

@@ -30,18 +30,6 @@ protected function setUp(): void
         parent::setUp();
     }
 
-    /**
-     * @dataProvider formatProvider
-     */
-    public function testFormat($pattern, $timestamp, $expected)
-    {
-        if (\PHP_VERSION_ID < 70105 && $timestamp instanceof \DateTimeImmutable) {
-            $this->markTestSkipped('PHP >= 7.1.5 required for DateTimeImmutable.');
-        }
-
-        parent::testFormat($pattern, $timestamp, $expected);
-    }
-
     /**
      * @dataProvider formatTimezoneProvider
      */