decrease runtime of regular_wall_nelder_mead_ok by reducing the spawnNumber.

Scenarios/ModelTests/TestOSM/scenarios/regular_wall_nelder_mead_ok.scenario

@@ -139,7 +139,7 @@
           "height" : 10.0,
           "type" : "RECTANGLE"
         },
-        "id" : -1
+        "id" : 3
       }, {
         "shape" : {
           "type" : "POLYGON",
@@ -157,7 +157,7 @@
             "y" : 0.5001
           } ]
         },
-        "id" : -1
+        "id" : 4
       }, {
         "shape" : {
           "type" : "POLYGON",
@@ -175,7 +175,7 @@
             "y" : -1.0E-4
           } ]
         },
-        "id" : -1
+        "id" : 5
       }, {
         "shape" : {
           "type" : "POLYGON",
@@ -193,7 +193,7 @@
             "y" : 9.4999
           } ]
         },
-        "id" : -1
+        "id" : 6
       }, {
         "shape" : {
           "type" : "POLYGON",
@@ -211,7 +211,7 @@
             "y" : 10.0001
           } ]
         },
-        "id" : -1
+        "id" : 7
       } ],
       "measurementAreas" : [ {
         "shape" : {
@@ -245,7 +245,7 @@
       "targetChangers" : [ ],
       "absorbingAreas" : [ ],
       "sources" : [ {
-        "id" : -1,
+        "id" : 2,
         "shape" : {
           "x" : 2.5,
           "y" : 2.5,
@@ -255,7 +255,7 @@
         },
         "interSpawnTimeDistribution" : "org.vadere.state.scenario.ConstantDistribution",
         "distributionParameters" : [ 1.0 ],
-        "spawnNumber" : 50,
+        "spawnNumber" : 5,
         "maxSpawnNumberTotal" : -1,
         "startTime" : 0.0,
         "endTime" : 0.0,