[svn r330] Implemented synchronized statements. Changed the tryfinally handlers to a more generalized EnclosingHandler. Changed ClassInfoS to be mutable so they can be used as locks. Added new BB after throw ala return/break etc.

module bug47;

bool func(bool a, bool b)
{
    if (a) b = false;
    return b;
}

void main()
{
    assert(func(0,0) == 0);
    assert(func(0,1) == 1);
    assert(func(1,0) == 0);
    assert(func(1,1) == 0);
}