Should TypeVariableBinding answer true for isClass() ?

I was surprised by TypeVariableBinding.isClass() answering true in org.eclipse.jdt.internal.compiler.lookup.ReferenceBinding.getAllEnumerableReferenceTypes() (the only call there)

Because it answers true and because it is not abstract, it gets added to permitted subtypes set in:

```
if (isClass() && (!isAbstract()))
permSet.add(this);
```
which causes bad things to happen down the road.

Perhaps the block should instead read:

```
if (isClass() && canBeInstantiated())
permSet.add(this);
```

The latter would address the problem I presently have, but this ticket is for the larger question. Should TVB answer true for isClass() ?