Bug 64070 fix, traits aliasing of collided methods

Here's a description https://bugs.php.net/bug.php?id=64070

Basically the problem can be described so:
We have a trait Foo that has a method bar()
We have a trait Bar that has a method bar()
Bar uses Foo, and to avoid collisions, it aliases Foo::bar() as foo()

Now the problem: when Foo::bar() copied to a Bar with alias foo(), its function_name (zend_function.common.function_name) remains as "bar". So when some other class or trait uses Bar, it receives Foo::bar() as bar, not as foo() and that causes a problem.