Add test `Set_max_speed_degenerate`

Inst_eddies/Tests/Input/SHPC_degenerate/orientation.txt

+anticyclones

Inst_eddies/Tests/short_tests.json

@@ -252,6 +252,27 @@
 	    ]
 	]
     },
+    {
+        "required":
+	[
+            ["$src_dir/Inst_eddies/Tests/Input/degenerated_SSH.nc", "h.nc"],
+            ["$src_dir/Inst_eddies/Tests/Input/degenerated_SSH.nc", "uv.nc"],
+            [
+		"$src_dir/Inst_eddies/Tests/Input/empty_outside_points.csv",
+		"outside_points.csv"
+	    ]
+        ],
+        "title": "Set_max_speed_degenerate",
+	"description": "The SSH value of the extremum is exactly equal to the SSH value of the point next to the extremum, eastward. This points is selected as the point with maximum azimuthal speed. Then good_contour returns a null polyline.",
+        "commands":
+	[
+	    ["mkdir", "SHPC"],
+	    [
+		"$build_dir/Inst_eddies/test_set_max_speed",
+		"$src_dir/Inst_eddies/Tests/Input/SHPC_degenerate"
+	    ]
+	]
+    },
     {
         "input": "&main_nml min_amp = 0./\n",
         "required": [