Python: add shared-CFG AstSig adapter (AstNodeImpl)

Preparatory refactor for the shared-CFG dataflow migration. Adds the
adapter that mediates between the Python AST and the shared
codeql.controlflow.ControlFlowGraph signature, plus the test suites
that validate the new CFG directly against this adapter. The public
facade is added in the following commit.

Library additions:

- semmle.python.controlflow.internal.AstNodeImpl — wraps Python's
  Stmt/Expr/Scope/Pattern and adds two synthetic kinds of node
  (BlockStmt for body slots, intermediate nodes for multi-operand
  boolean expressions) to satisfy the shared CFG signature.

- lib/printCfgNew.ql — debug/visualisation query for the new CFG.

- consistency-queries/CfgConsistency.ql — consistency query running
  the shared CFG's standard checks against Python.

Test additions (all driven directly off AstNodeImpl):

- ControlFlow/bindings/* — annotation-driven SSA-binding tests
  (annassign, compound, comprehension, decorated, except_handler,
  imports, match_pattern, parameters, simple, type_params,
  walrus_starred, with_stmt, dead_under_no_raise).

- ControlFlow/evaluation-order/NewCfg*.ql — mirrors of the existing
  OldCfg evaluation-order self-validation suite, run against the
  new CFG via NewCfgImpl.qll.

- Minor extensions to existing test_if.py / test_boolean.py +
  cosmetic .expected churn on a handful of OldCfg tests.

No dataflow, SSA, or production query is migrated yet.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: yoff

python/ql/consistency-queries/CfgConsistency.ql

@@ -0,0 +1,2 @@
+import semmle.python.controlflow.internal.AstNodeImpl
+import ControlFlow::Consistency

python/ql/lib/printCfgNew.ql

@@ -0,0 +1,45 @@
+/**
+ * @name Print CFG (New)
+ * @description Produces a representation of a file's Control Flow Graph
+ *              using the new shared control flow library.
+ *              This query is used by the VS Code extension.
+ * @id python/print-cfg
+ * @kind graph
+ * @tags ide-contextual-queries/print-cfg
+ */
+
+private import python as Py
+import semmle.python.controlflow.internal.AstNodeImpl
+
+external string selectedSourceFile();
+
+private predicate selectedSourceFileAlias = selectedSourceFile/0;
+
+external int selectedSourceLine();
+
+private predicate selectedSourceLineAlias = selectedSourceLine/0;
+
+external int selectedSourceColumn();
+
+private predicate selectedSourceColumnAlias = selectedSourceColumn/0;
+
+module ViewCfgQueryInput implements ControlFlow::ViewCfgQueryInputSig<Py::File> {
+  predicate selectedSourceFile = selectedSourceFileAlias/0;
+
+  predicate selectedSourceLine = selectedSourceLineAlias/0;
+
+  predicate selectedSourceColumn = selectedSourceColumnAlias/0;
+
+  predicate cfgScopeSpan(
+    Ast::Callable callable, Py::File file, int startLine, int startColumn, int endLine,
+    int endColumn
+  ) {
+    exists(Py::Scope scope |
+      scope = callable.asScope() and
+      file = scope.getLocation().getFile() and
+      scope.getLocation().hasLocationInfo(_, startLine, startColumn, endLine, endColumn)
+    )
+  }
+}
+
+import ControlFlow::ViewCfgQuery<Py::File, ViewCfgQueryInput>