remove_fin: ignore more useless transitions

Do not clone transitions that are necessarily part of on accepting
cycle in the main copy of the automaton.

* spot/twaalgos/remfin.cc: Use propagate_marks_vector to ignore more
edges.
* tests/core/remfin.test, tests/python/remfin.py,
tests/python/automata.ipynb: Adjust.
* tests/sanity/style.test: Do not choke on C++17 if statements with
initializer.

tests/core/remfin.test

@@ -877,14 +877,12 @@ State: 0
 State: 1
 [2] 0
 [!2] 1
-[0&2] 2
 [0&!2] 3
 [2] 4
 [!2] 5
 State: 2
 [0] 2 {0 2}
 State: 3
-[0&2] 2 {0 2}
 [0&!2] 3 {0}
 State: 4
 [1 | 2] 4 {1 2}
@@ -1457,7 +1455,7 @@ State: 3
 [1] 3
 --END--
 HOA: v1
-States: 6
+States: 5
 Start: 0
 AP: 3 "a" "b" "c"
 acc-name: Buchi
@@ -1468,25 +1466,20 @@ State: 0
 [t] 0
 [!1&!2] 1
 [0] 2
-[1 | 2] 4
+[1 | 2] 3
 State: 1
 [2] 0
 [!2] 1
-[0&2] 2
-[0&!2] 3
-[2] 4
-[!2] 5
+[2] 3
+[!2] 4
 State: 2
 [0] 2 {0}
 State: 3
-[0&2] 2
-[0&!2] 3
+[1 | 2] 3 {0}
+[!1&!2] 4
 State: 4
-[1 | 2] 4 {0}
-[!1&!2] 5
-State: 5
-[2] 4 {0}
-[!2] 5
+[2] 3 {0}
+[!2] 4
 --END--
 EOF