[svn r374] Move label target basic block from AST to IRFunction. This is a first step to allowing labels to be emitted multiple times. (for instance within finally blocks)

module condexp;

int f()
{
    return 42;
}

void main()
{
    int i = f() < 25 ? -1 : 1;
    /*int j = f() > 25 ? 1 : -1;
    assert(i);
    assert(!j);*/
}