evaluate: Do not attack too early when first 5 moves (2)

e67dfc5645  was invalidated by a change
in the parent commit, so it was reworked.

If first 4 moves is placing at star point, move 5 temporarily use depth 1 search
in order to make sure white player do not attack and try to block black.
(For 9ms, star point is b4/d6/f4/d2)

This changed the white's moves.

For nine men's morris:

If first 4 moves is:
1. b4 d6
2. f4 d2
Next move, white will place at a4/c4/e4/g4,
now changed to place at d7/d5/d3/d1

If first 4 moves is:
1. b4 f4
2. d6 d2
Next move, white will place at b6, it is not wrong,
Note: This is the difference between e67dfc56.

Play 100 games against with v1.1.27, Result:
27% : 11% : 62%
8% : 32% : 60%
Sum: 29.5% : 9.5% : 61%

src/mills.cpp

@@ -485,7 +485,7 @@ Depth get_search_depth(const Position *pos)
             if (gameOptions.getDrawOnHumanExperience()) {
                 if (index == 4 &&
                     is_star_squares_full(const_cast<Position *>(pos))) {
-                    d = 1;  // In order to use Mobility
+                    d = 3;  // In order to use Mobility
                 }
             }