Dataflow: Fix qltest.

java/ql/src/semmle/code/java/dataflow/internal/DataFlowImplCommon.qll

@@ -300,6 +300,15 @@ private module Cached {
         )
       }
 
+      /**
+       * Holds if `arg` flows to `out` through a call using only
+       * value-preserving steps and a single read step, not taking call
+       * contexts into account, thus representing a getter-step.
+       */
+      predicate getterStep(ArgumentNode arg, Content c, Node out) {
+        argumentValueFlowsThrough(arg, TReadStepTypesSome(_, c, _), out)
+      }
+
       /**
        * Holds if `p` can flow to a return node of kind `kind` in the same
        * callable using only value-preserving steps and possibly a single read