C++: Fix the definition of GlobalNamespace.getADeclaration()

Globals can still have declarations in declaration statements.
We already rule out local variables etc via the isTopLevel check,
so we don't need to consider DeclStmt.

Author: ian-semmle

cpp/ql/src/semmle/code/cpp/Namespace.qll

@@ -190,11 +190,6 @@ class GlobalNamespace extends Namespace {
 
   override Declaration getADeclaration() {
     suppressWarningForUnused(this) and
-    not exists(DeclStmt d |
-      d.getADeclaration() = result and
-      not result instanceof Function
-    ) and
-    not exists(ConditionDeclExpr cde | cde.getVariable() = result) and
     result.isTopLevel() and
     not namespacembrs(_, unresolveElement(result))
   }

cpp/ql/test/library-tests/namespaces/namespaces/decls.expected

@@ -5,9 +5,9 @@
 | file://:0:0:0:0 | (global namespace) | file://:0:0:0:0 | operator= | false |
 | file://:0:0:0:0 | (global namespace) | file://:0:0:0:0 | overflow_arg_area | false |
 | file://:0:0:0:0 | (global namespace) | file://:0:0:0:0 | reg_save_area | false |
+| file://:0:0:0:0 | (global namespace) | namespaces.cpp:40:5:40:13 | globalInt | true |
 | file://:0:0:0:0 | (global namespace) | namespaces.cpp:42:6:42:18 | globalIntUser | true |
 | file://:0:0:0:0 | <none> | file://:0:0:0:0 | auto | false |
-| file://:0:0:0:0 | <none> | namespaces.cpp:40:5:40:13 | globalInt | true |
 | file://:0:0:0:0 | B | namespaces.cpp:32:7:32:7 | x | true |
 | namespaces.cpp:11:13:11:13 | C::D | file://:0:0:0:0 | p#0 | false |
 | namespaces.cpp:11:13:11:13 | C::D | file://:0:0:0:0 | p#0 | false |