[phpunit 12] Add ExplicitMockExpectsCallRector

[TomasVotruba]

Following snippets are no longer valid in PHPUnit 12:

$someMock = $this->createMock(\stdClass::class);
$someMock->method('some');

and synonymous:

$someMock = $this->createMock(\stdClass::class);
$someMock->expectx($this->any())->method('some');