ECJ reports Incorrect type mismatch error

This was originally reported as part of [bug 481332](https://bugs.eclipse.org/bugs/show_bug.cgi?id=481332#c15) as I suspected that fix to be causing this. But since it's been a while since it was fixed, it makes sense to have a new issue.

The code in question is this:
```
class Parent {}
class Child extends Parent {}
class Container {}
public class X {
public static int method(Container par) {
return 0;
}
public static void main(String args[]) {
if (method(new Container<>()) == 0) {
System.out.println("Zero");
}
}
}
```
Bound mismatch: The type ? super T is not a valid substitute for the bounded parameter of the type Container

which is reported by PTB#boundCheck(), line number 139.

Copying @stephan-herrmann for comments.