Add test for backtrace with aliased trait

[mvorisek]

see https://3v4l.org/uVm7l, in PHP 7.4, backtrace was wrong when private aliased method was redeclared in child class

I belive this was fixed in 53efa1b

but there is only one test /w Reflection

this test asserts the backtrace is correct as some frameworks may assert some security features on it

[mvorisek]

are there any objections before merging?

[cmb69]

Since the test isn't about actual reflection, I'd put it under Zend/tests. Otherwise this is good to me.

[mvorisek]

Test moved

[arnaud-lb]

Thank you!