DX: remove recursion from AbstractIntegrationTestCase::testIntegration

[kubawerlos]

The (re)moved testIntegration call was inside of doTest (called in line 148, which is inside of testIntegration).

[coveralls]

coverage: 94.795%. remained the same
when pulling fc4eebf on 6b7562617765726c6f73:dx_AbstractIntegrationTestCase
into 34b7d63 on PHP-CS-Fixer:master.

[keradus]

i'm mid-mid here.

this approach means whenever someone calling ->doTest(), they shall always call it twice. I'm not sure if it's good.
(i know there are not so many cases we call it, but imagine we make this AbstractIntegrationTestCase public ultimately, for libraries of custom repos)

maybe they can continue to call it once, and in doTest we do like

function doTest() {
    check reqs for PHP...

    $this->verifyIntegration($expected, $input); // of course, full IntegrationCase to be passed
    $this->verifyIntegration($expected, null);
}

or even
function doTest() {
    check reqs for PHP...

    foreach ([$epected, $input], [$expected, null])
        regular testing logic....
}

[kubawerlos]

Wasn't the previous implementation even worse? Anyone calling doTest would also call testIntegration. We can refactor this later, this one is only about removing recursion.

[keradus]

Wasn't the previous implementation even worse?

thus I gave the approval, right? ;)