Merge pull request github#5658 from MathiasVP/fix-partial-def-diff-test

C++: Fix performance in test

Author: rdmarsh2

cpp/ql/test/library-tests/dataflow/fields/partial-definition-diff.ql

@@ -19,15 +19,19 @@ class IRPartialDefNode extends IRNode {
   override string toString() { result = n.asPartialDefinition().toString() }
 }
 
-from Node node, AST::Node astNode, IR::Node irNode, string msg
+from Node node, string msg
 where
-  node.asIR() = irNode and
-  exists(irNode.asPartialDefinition()) and
-  not exists(AST::Node otherNode | otherNode.asPartialDefinition() = irNode.asPartialDefinition()) and
+  exists(IR::Node irNode, Expr partial |
+    node.asIR() = irNode and
+    partial = irNode.asPartialDefinition() and
+    not exists(AST::Node otherNode | otherNode.asPartialDefinition() = partial)
+  ) and
   msg = "IR only"
   or
-  node.asAST() = astNode and
-  exists(astNode.asPartialDefinition()) and
-  not exists(IR::Node otherNode | otherNode.asPartialDefinition() = astNode.asPartialDefinition()) and
+  exists(AST::Node astNode, Expr partial |
+    node.asAST() = astNode and
+    partial = astNode.asPartialDefinition() and
+    not exists(IR::Node otherNode | otherNode.asPartialDefinition() = partial)
+  ) and
   msg = "AST only"
 select node, msg