C++: Annotate tellDifferent with template status

This is helpful for turning real-world cases into test cases.

Author: jbj

cpp/ql/test/library-tests/syntax-zoo/tellDifferent.expected

@@ -1,3 +1,3 @@
-| staticlocals__staticlocals_f2 | file://:0:0:0:0 | call to C | staticlocals.cpp:30:1:30:1 | return ... | Standard edge, only from QL |
-| staticlocals__staticlocals_f2 | file://:0:0:0:0 | initializer for c | file://:0:0:0:0 | call to C | Standard edge, only from QL |
-| staticlocals__staticlocals_f2 | staticlocals.cpp:29:5:29:17 | declaration | file://:0:0:0:0 | initializer for c | Standard edge, only from QL |
+| staticlocals__staticlocals_f2 | file://:0:0:0:0 | call to C | staticlocals.cpp:30:1:30:1 | return ... | Standard edge, only from QL |  |
+| staticlocals__staticlocals_f2 | file://:0:0:0:0 | initializer for c | file://:0:0:0:0 | call to C | Standard edge, only from QL |  |
+| staticlocals__staticlocals_f2 | staticlocals.cpp:29:5:29:17 | declaration | file://:0:0:0:0 | initializer for c | Standard edge, only from QL |  |

cpp/ql/test/library-tests/syntax-zoo/tellDifferent.ql

@@ -1,5 +1,13 @@
 import Compare
 
+string describeTemplate(ControlFlowNode node) {
+  node.isFromTemplateInstantiation(_) and
+  result = "instantiation"
+  or
+  node.isFromUninstantiatedTemplate(_) and
+  result = "uninstantiated"
+}
+
 from ControlFlowNode n1, ControlFlowNode n2, string msg
 where differentEdge(n1, n2, msg)
-select getScopeName(n1), n1, n2, msg
+select getScopeName(n1), n1, n2, msg, concat(describeTemplate(n1), ", ")