Fix a bug in nested context code that occured when calling a function nested in the outermost scope with a context frame from a function using a more nested context frame.

module bug8;

void main()
{
    s = newS();
}

S* s;

struct S
{
    int i;
}

S* newS()
{
    auto tmp = new S;
    tmp.i = 4;
    return tmp;
}