C++: Accept changes in constant_func test

Author: igfoo

cpp/ql/test/library-tests/ir/constant_func/constant_func.cpp

@@ -38,6 +38,11 @@ int UnreachableViaGoto() {
   return 0;
 }
 
+/*
+The unaliased IR uses the raw IR's dead code elimination and constant
+analysis, so it isn't able to tell that the `return 1`s are dead code,
+and thus doesn't know that this always returns the same value.
+*/
 int UnreachableIf(bool b) {
   int x = 5;
   int y = 10;

cpp/ql/test/library-tests/ir/constant_func/constant_func.expected

@@ -2,5 +2,4 @@
 | constant_func.cpp:5:5:5:21 | IR: ReturnConstantPhi | 7 |
 | constant_func.cpp:25:5:25:25 | IR: ReturnConstantPhiLoop | 7 |
 | constant_func.cpp:34:5:34:22 | IR: UnreachableViaGoto | 0 |
-| constant_func.cpp:41:5:41:17 | IR: UnreachableIf | 0 |
-| constant_func.cpp:62:5:62:16 | IR: DoWhileFalse | 1 |
+| constant_func.cpp:67:5:67:16 | IR: DoWhileFalse | 1 |