C++: Fix comments in tests

cpp/ql/test/query-tests/Likely Bugs/Likely Typos/ExprHasNoEffect/autoconf/conftest.c

@@ -1,6 +1,6 @@
 #include "conftest.h"
 
 int main2() {
-  strlen(""); // GOOD: the source file occurs in a `CMakeFiles/CMakeScratch/TryCompile-...` directory
+  strlen(""); // GOOD: conftest files are ignored
   return 0;
 }

cpp/ql/test/query-tests/Likely Bugs/Likely Typos/ExprHasNoEffect/autoconf/conftest.c.c

@@ -1,6 +1,6 @@
 #include "conftest.h"
 
 int main3() {
-  strlen(""); // GOOD: the source file occurs in a `CMakeFiles/CMakeScratch/TryCompile-...` directory
+  strlen(""); // BAD: not a `conftest` file, as `conftest` is not directly followed by the extension or a sequence of numbers.
   return 0;
 }

cpp/ql/test/query-tests/Likely Bugs/Likely Typos/ExprHasNoEffect/autoconf/conftest.cpp

@@ -1,6 +1,6 @@
 #include "conftest.h"
 
 int main4() {
-  strlen(""); // GOOD: the source file occurs in a `CMakeFiles/CMakeScratch/TryCompile-...` directory
+  strlen(""); // GOOD: conftest files are ignored
   return 0;
 }

cpp/ql/test/query-tests/Likely Bugs/Likely Typos/ExprHasNoEffect/autoconf/conftest123.c

@@ -1,6 +1,6 @@
 #include "conftest.h"
 
 int main5() {
-  strlen(""); // GOOD: the source file occurs in a `CMakeFiles/CMakeScratch/TryCompile-...` directory
+  strlen(""); // GOOD: conftest files are ignored
   return 0;
 }

cpp/ql/test/query-tests/Likely Bugs/Likely Typos/ExprHasNoEffect/autoconf/conftest_abc.c

@@ -1,6 +1,6 @@
 #include "conftest.h"
 
 int main1() {
-  strlen(""); // GOOD: the source file occurs in a `CMakeFiles/CMakeScratch/TryCompile-...` directory
+  strlen(""); // BAD: not a `conftest` file, as `conftest` is not directly followed by the extension or a sequence of numbers.
   return 0;
 }