Fix Instability in PML with PSATD (ECP-WarpX#2558)

* Fix Instability in PML with PSATD

Damping in PML should be applied before the communications between the regular grids and PML, and between PML grids take place, otherwise the ghost cells are filled with lagged information, which results in an instability. Closes ECP-WarpX#2525.

* Update checksum of the pml_psatd_dive_divb_cleaning test

Regression/Checksum/benchmarks_json/pml_psatd_dive_divb_cleaning.json

@@ -1,11 +1,11 @@
 {
   "lev=0": {
-    "Bx": 1.3582454274967736e-08,
-    "By": 1.3585628519855815e-08,
-    "Bz": 1.3594037646470728e-08,
-    "Ex": 18.75779441734614,
-    "Ey": 18.75937784792576,
-    "Ez": 18.753302211359724,
+    "Bx": 1.357999256781357e-08,
+    "By": 1.358274729423031e-08,
+    "Bz": 1.358525756954841e-08,
+    "Ex": 1.874000101543667e+01,
+    "Ey": 1.873784914641192e+01,
+    "Ez": 1.873787090565788e+01,
     "rho": 0.00017408482555034496
   }
-}
+}

Source/Evolve/WarpXEvolve.cpp

@@ -408,6 +408,10 @@ WarpX::OneStep_nosub (Real cur_time)
         }
         PushPSATD();
 
+        if (do_pml) {
+            DampPML();
+        }
+
         if (use_hybrid_QED) {
             FillBoundaryE(guard_cells.ng_alloc_EB);
             FillBoundaryB(guard_cells.ng_alloc_EB);
@@ -428,7 +432,6 @@ WarpX::OneStep_nosub (Real cur_time)
         NodalSync(Bfield_fp, Bfield_cp);
 
         if (do_pml) {
-            DampPML();
             NodalSyncPML();
         }
     } else {