Data flow: Reduce caching

These predicates are now cached in the shared implementation.

ql/src/codeql_ruby/dataflow/internal/DataFlowPrivate.qll

@@ -177,18 +177,17 @@ private module Cached {
 
   cached
   newtype TContent = TTodoContent() // stub
-
-  /** Holds if `n` should be hidden from path explanations. */
-  cached
-  predicate nodeIsHidden(Node n) {
-    exists(Ssa::Definition def | def = n.(SsaDefinitionNode).getDefinition() |
-      def instanceof Ssa::PhiNode
-    )
-  }
 }
 
 import Cached
 
+/** Holds if `n` should be hidden from path explanations. */
+predicate nodeIsHidden(Node n) {
+  exists(Ssa::Definition def | def = n.(SsaDefinitionNode).getDefinition() |
+    def instanceof Ssa::PhiNode
+  )
+}
+
 /** An SSA definition, viewed as a node in a data flow graph. */
 class SsaDefinitionNode extends NodeImpl, TSsaDefinitionNode {
   Ssa::Definition def;
@@ -308,7 +307,6 @@ import ParameterNodes
 /** A data-flow node that represents a call argument. */
 abstract class ArgumentNode extends Node {
   /** Holds if this argument occurs at the given position in the given call. */
-  cached
   abstract predicate argumentOf(DataFlowCall call, int pos);
 
   /** Gets the call in which this node is an argument. */
@@ -420,7 +418,6 @@ import ReturnNodes
 /** A data-flow node that represents the output of a call. */
 abstract class OutNode extends Node {
   /** Gets the underlying call, where this node is a corresponding output of kind `kind`. */
-  cached
   abstract DataFlowCall getCall(ReturnKind kind);
 }