[8.x ]Refactor setMethods to onlyMethods and addMethods

`MockBuilder::setMethods` is soft deprecated as of PHPUnit 9
So I refactor the test.

Please merge laravel#35474  after merging

sebastianbergmann/phpunit#3687

Author: soilSpoon

tests/Database/DatabaseConnectionTest.php

@@ -62,7 +62,7 @@ public function testSelectProperlyCallsPDO()
         $writePdo = $this->getMockBuilder(DatabaseConnectionTestMockPDO::class)->onlyMethods(['prepare'])->getMock();
         $writePdo->expects($this->never())->method('prepare');
         $statement = $this->getMockBuilder('PDOStatement')
-            ->setMethods(['setFetchMode', 'execute', 'fetchAll', 'bindValue'])
+            ->onlyMethods(['setFetchMode', 'execute', 'fetchAll', 'bindValue'])
             ->getMock();
         $statement->expects($this->once())->method('setFetchMode');
         $statement->expects($this->once())->method('bindValue')->with('foo', 'bar', 2);

tests/Validation/ValidationValidatorTest.php

@@ -2872,7 +2872,7 @@ public function testValidateImage()
         $v = new Validator($trans, ['x' => $file7], ['x' => 'Image']);
         $this->assertTrue($v->passes());
 
-        $file2 = $this->getMockBuilder(UploadedFile::class)->setMethods(['guessExtension', 'getClientOriginalExtension'])->setConstructorArgs($uploadedFile)->getMock();
+        $file2 = $this->getMockBuilder(UploadedFile::class)->onlyMethods(['guessExtension', 'getClientOriginalExtension'])->setConstructorArgs($uploadedFile)->getMock();
         $file2->expects($this->any())->method('guessExtension')->willReturn('jpg');
         $file2->expects($this->any())->method('getClientOriginalExtension')->willReturn('jpg');
         $v = new Validator($trans, ['x' => $file2], ['x' => 'Image']);