C++: Remove test that is no longer relevant

cpp/ql/test/library-tests/builtins/functions_file/builtins.txt

@@ -1,2 +0,0 @@
-__builtin_foobar(i)i
-__builtin_malloc(i,i,i,f*)f

cpp/ql/test/library-tests/builtins/functions_file/isbuiltin.expected

@@ -1,4 +0,0 @@
-| file://:0:0:0:0 | __builtin_add_overflow | true | 0 | file://:0:0:0:0 | bool |
-| file://:0:0:0:0 | __builtin_foobar | true | 1 | file://:0:0:0:0 | int |
-| file://:0:0:0:0 | __builtin_malloc | true | 4 | file://:0:0:0:0 | float |
-| test.c:1:6:1:6 | f | false | 3 | file://:0:0:0:0 | long |

cpp/ql/test/library-tests/builtins/functions_file/isbuiltin.ql

@@ -1,5 +0,0 @@
-import cpp
-
-from Function f, boolean isBuiltin
-where if f instanceof BuiltInFunction then isBuiltin = true else isBuiltin = false
-select f, isBuiltin, f.getNumberOfParameters(), f.getType()

cpp/ql/test/library-tests/builtins/functions_file/test.c

@@ -1,20 +0,0 @@
-long f(int a, int b, int c) {
-  // A builtin from the builtin_functions_file.
-  int i1 = __builtin_foobar(a);
-
-  // A builtin that's not in the file, but the extractor should handle, given the
-  // --gnu_version flag we pass in.
-  int i2;
-  __builtin_add_overflow(a, b, &i2);
-
-  // A builtin that would normally be defined by the extractor with a type
-  // expecting it to be called like this:
-  //void* x = __builtin_malloc(a);
-  // But we override the type in the builtin_functions_file so it's called like
-  // this:
-  float f1, f2;
-  f1 = __builtin_malloc(a, b, c, &f2);
-
-  return 42;
-}
-// semmle-extractor-options: --gnu_version 50100 --edg --builtin_functions_file --edg ${testdir}/builtins.txt