Armonize test binaries.

tests/bin/Marabou

-#!/bin/sh
+#!/bin/sh -e
 
 
 case $1 in
@@ -6,7 +6,9 @@ case $1 in
         echo "1.0.+"
         ;;
     *)
+        echo "PWD: $(pwd)"
         echo "NN: $1"
+        test -e $1 || (echo "Cannot find the NN file" && exit 1)
         echo "Goal:"
         cat $2
         echo "Unknown"

tests/bin/pyrat.py

@@ -8,7 +8,7 @@ case $1 in
     *)
         echo "PWD: $(pwd)"
         echo "NN: $2"
-        test -e $2 || (echo "Can't find the file" && exit 1)
+        test -e $2 || (echo "Cannot find the NN file" && exit 1)
         echo "Goal:"
         cat $4
         echo "Result = Unknown"