Update benchmarks for test_3d_magnetostatic_eb

This uses Neumann BC and for the old version no correction
was being done on the boundary.

Regression/Checksum/benchmarks_json/test_3d_magnetostatic_eb.json

@@ -1,21 +1,21 @@
 {
   "lev=0": {
-    "Az": 11.358663326449284,
-    "Bx": 111.55929407644248,
-    "By": 111.55929407644244,
-    "Ex": 31257180402.55472,
-    "Ey": 31257180402.55473,
-    "jz": 1034841325.9848926,
-    "phi": 3143521213.0157924,
-    "rho": 3.449203918900721
+    "Az": 11.358663299932457,
+    "Bx": 111.55929615203162,
+    "By": 111.55929615203165,
+    "Ex": 31463410849.74626,
+    "Ey": 31463410849.746258,
+    "jz": 1034841323.6861029,
+    "phi": 3164328318.15416,
+    "rho": 3.4565836983918676
   },
   "beam": {
-    "particle_momentum_x": 1.3604657334742729e-21,
-    "particle_momentum_y": 1.3604657334742772e-21,
-    "particle_momentum_z": 7.150873450281544e-16,
-    "particle_position_x": 11163.99997371537,
-    "particle_position_y": 11163.999973715368,
-    "particle_position_z": 131662.50031035842,
+    "particle_momentum_x": 1.3829464728617761e-21,
+    "particle_momentum_y": 1.3829464728617792e-21,
+    "particle_momentum_z": 7.150871807235339e-16,
+    "particle_position_x": 11163.99997715059,
+    "particle_position_y": 11163.999977150592,
+    "particle_position_z": 131662.5003102683,
     "particle_weight": 20895107655113.465
   }
-}
+}