Fix variable order printer

Improve tests on printers

scripts/ci_test_printers.sh

@@ -2,14 +2,19 @@
 
 ### Test printer 
 
-# Needed for evm printer
-pip install evm-cfg-builder
+cd tests/ast-parsing/compile || exit
 
-if ! slither "tests/*.json" --print all --json -; then
-    echo "Printer tests failed"
+# Do not test the evm printer,as it needs a refactoring
+ALL_PRINTERS="cfg,constructor-calls,contract-summary,data-dependency,echidna,function-id,function-summary,modifiers,call-graph,human-summary,inheritance,inheritance-graph,slithir,slithir-ssa,vars-and-auth,require,variable-order"
+
+# Only test 0.5.17 to limit test time
+for file in *0.5.17-compact.zip; do
+  if ! slither "$file" --print "$ALL_PRINTERS" > /dev/null 2>&1 ; then
+    echo "Printer failed"
+    echo "$file"
     exit 1
-fi
+  fi
+done
 
-solc-select use "0.5.1"
 
 slither examples/scripts/test_evm_api.sol --print evm 

slither/printers/summary/variable_order.py

@@ -29,7 +29,7 @@ class VariableOrder(AbstractPrinter):
             table = MyPrettyTable(["Name", "Type", "Slot", "Offset"])
             for variable in contract.state_variables_ordered:
                 if not variable.is_constant:
-                    slot, offset = self.slither.storage_layout_of(contract, variable)
+                    slot, offset = contract.compilation_unit.storage_layout_of(contract, variable)
                     table.add_row([variable.canonical_name, str(variable.type), slot, offset])
 
             all_tables.append((contract.name, table))