Remove test suite's live HTTP request to example.com (laravel#38410)

Event Illuminate\Http\Client\Events\ConnectionFailed can randomly be
dispatched by testClonedClientsWorkSuccessfullyWithTheRequestObject()
on some test suite runs which causes this test case to fail. This HTTP
client test is making an actual HTTP request to example.com that can
intermittently fail. Remove this unreliable external dependency.

Mock the response so the Guzzle handler middleware stack still runs to
dispatch events RequestSending & ResponseReceived.

Also move Mockery `m::close()` into PHPUnit's `tearDown()` lifecycle
since failed test cases will cause registered mocks to leak into
subsequent test cases.

tests/Http/HttpClientTest.php

@@ -36,6 +36,11 @@ protected function setUp(): void
         $this->factory = new Factory;
     }
 
+    protected function tearDown(): void
+    {
+        m::close();
+    }
+
     public function testStubbedResponsesAreReturnedAfterFaking()
     {
         $this->factory->fake();
@@ -936,8 +941,6 @@ public function testTheRequestSendingAndResponseReceivedEventsAreFiredWhenAReque
         $factory->post('https://example.com');
         $factory->patch('https://example.com');
         $factory->delete('https://example.com');
-
-        m::close();
     }
 
     public function testTheRequestSendingAndResponseReceivedEventsAreFiredWhenARequestIsSentAsync()
@@ -957,8 +960,6 @@ public function testTheRequestSendingAndResponseReceivedEventsAreFiredWhenAReque
                 $pool->delete('https://example.com'),
             ];
         });
-
-        m::close();
     }
 
     public function testTheTransferStatsAreCalledSafelyWhenFakingTheRequest()
@@ -988,13 +989,12 @@ public function testClonedClientsWorkSuccessfullyWithTheRequestObject()
         $events->shouldReceive('dispatch')->once()->with(m::type(ResponseReceived::class));
 
         $factory = new Factory($events);
+        $factory->fake(['example.com' => $factory->response('foo', 200)]);
 
         $client = $factory->timeout(10);
         $clonedClient = clone $client;
 
         $clonedClient->get('https://example.com');
-
-        m::close();
     }
 
     public function testRequestIsMacroable()