C++: Add failing test.

Author: MathiasVP

cpp/ql/test/library-tests/dataflow/taint-tests/localTaint.expected

@@ -6643,6 +6643,8 @@ WARNING: Module TaintTracking has been deprecated and may be removed in future (
 | taint.cpp:729:27:729:32 | endptr | taint.cpp:729:26:729:32 | & ... |  |
 | taint.cpp:731:7:731:12 | ref arg endptr | taint.cpp:732:8:732:13 | endptr |  |
 | taint.cpp:732:8:732:13 | endptr | taint.cpp:732:7:732:13 | * ... | TAINT |
+| taint.cpp:738:17:738:31 | call to indirect_source | taint.cpp:739:30:739:35 | source |  |
+| taint.cpp:739:22:739:28 | call to realloc | taint.cpp:740:7:740:10 | dest |  |
 | vector.cpp:16:43:16:49 | source1 | vector.cpp:17:26:17:32 | source1 |  |
 | vector.cpp:16:43:16:49 | source1 | vector.cpp:31:38:31:44 | source1 |  |
 | vector.cpp:17:21:17:33 | call to vector | vector.cpp:19:14:19:14 | v |  |

cpp/ql/test/library-tests/dataflow/taint-tests/taint.cpp

@@ -730,4 +730,12 @@ void test_strtol(char *source) {
 	sink(l); // $ ast,ir
 	sink(endptr); // $ ast,ir
 	sink(*endptr); // $ ast,ir
+}
+
+void *realloc(void *, size_t);
+
+void test_realloc() {
+	char *source = indirect_source();
+	char *dest = (char*)realloc(source, 16);
+	sink(dest); // $ MISSING: ast,ir
 }