Convert A18-9-4 to use the new dataflow library

The query seemed to depend on a bug in the old dataflow library
before, where `asDefiningArgument` could return the function call
instead of its argument.

Author: jketema

cpp/autosar/src/rules/A18-9-4/ArgumentToForwardSubsequentlyUsed.ql

@@ -14,13 +14,13 @@
 import cpp
 import codingstandards.cpp.autosar
 import codingstandards.cpp.standardlibrary.Utility
-import semmle.code.cpp.dataflow.DataFlow
+import semmle.code.cpp.dataflow.new.DataFlow
 
 from StdForwardCall f, Access a
 where
   not isExcluded(a, MoveForwardPackage::movedFromObjectReadAccessedQuery()) and
   exists(DataFlow::DefinitionByReferenceNode def |
-    def.asDefiningArgument() = f and
+    def.asDefiningArgument() = f.getArgument(0) and
     DataFlow::localFlow(def, DataFlow::exprNode(a))
   )
 select a, "The argument $@ of `std::forward` may be indeterminate when accessed at this location.",

cpp/autosar/test/rules/A18-9-4/ArgumentToForwardSubsequentlyUsed.expected

@@ -1,4 +1 @@
-WARNING: module 'DataFlow' has been deprecated and may be removed in future (ArgumentToForwardSubsequentlyUsed.ql:22,10-18)
-WARNING: module 'DataFlow' has been deprecated and may be removed in future (ArgumentToForwardSubsequentlyUsed.ql:24,5-13)
-WARNING: module 'DataFlow' has been deprecated and may be removed in future (ArgumentToForwardSubsequentlyUsed.ql:24,30-38)
 | test.cpp:8:5:8:6 | t2 | The argument $@ of `std::forward` may be indeterminate when accessed at this location. | test.cpp:7:45:7:46 | t2 | t2 |