coccinelle: Add rules to find str_false_true() replacements

As done with str_true_false(), add checks for str_false_true()
opportunities. A simple test can find over 9 cases currently
exist in the tree.

Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>