Remove grid stretch parameters from simulation inputs (#430)

Author: haochey

toolchain/mfc/run/case_dicts.py

@@ -123,7 +123,7 @@
     SIMULATION.append(f'bc_{cmp}%ve1')
     SIMULATION.append(f'bc_{cmp}%ve2')
     SIMULATION.append(f'bc_{cmp}%ve3')
-    for prepend in ["domain%beg", "domain%end", "a", "b"]:
+    for prepend in ["domain%beg", "domain%end"]:
         SIMULATION.append(f"{cmp}_{prepend}")
 
 for wrt_id in range(1,10+1):