acc: fix maybe_accepting() on Fin(x)|Fin(y)|Fin(z)

Fixes #271, reported by Henrich Lauko.

* spot/twa/acc.cc (maybe_accepting): Fix handling in case
of disjunction of Fin.
* tests/core/scc.test, tests/python/accparse2.py: Add more
tests.

tests/core/scc.test

@@ -103,3 +103,35 @@ EOF
 run 0 autfilt --decompose-scc=1 -F aut> out
 cat out
 diff out ref
+
+
+# From issue #271, reported by Henrich Lauko.
+cat >in.hoa <<EOF
+HOA: v1
+States: 4
+Start: 2
+AP: 2 "p1" "p0"
+acc-name: generalized-co-Buchi 2
+Acceptance: 2 Fin(0)|Fin(1)
+properties: trans-labels explicit-labels state-acc complete
+properties: deterministic
+--BODY--
+State: 0 {0}
+[1] 0
+[!1] 1
+State: 1 {0 1}
+[1] 0
+[!1] 1
+State: 2
+[0&1] 0
+[0&!1] 1
+[!0&1] 2
+[!0&!1] 3
+State: 3 {1}
+[0&1] 0
+[0&!1] 1
+[!0&1] 2
+[!0&!1] 3
+--END--
+EOF
+test 2 = `autfilt --stats=%[a]c in.hoa`