Add a lot more scalar types and go strict in Logger

tests/Monolog/Handler/WhatFailureGroupHandlerTest.php

@@ -112,7 +112,7 @@ class ExceptionTestHandler extends TestHandler
     /**
      * {@inheritdoc}
      */
-    public function handle(array $record)
+    public function handle(array $record): bool
     {
         parent::handle($record);
 

tests/Monolog/LoggerTest.php

@@ -182,17 +182,6 @@ class LoggerTest extends \PHPUnit_Framework_TestCase
         $logger->popProcessor();
     }
 
-    /**
-     * @covers Monolog\Logger::pushProcessor
-     * @expectedException InvalidArgumentException
-     */
-    public function testPushProcessorWithNonCallable()
-    {
-        $logger = new Logger(__METHOD__);
-
-        $logger->pushProcessor(new \stdClass());
-    }
-
     /**
      * @covers Monolog\Logger::addRecord
      */