C++: Rename PointerWrapAround to PointerOverflow

Overflow was the terminology I found for this in the C standard (C11
6.5.6-8).

cpp/ql/test/query-tests/Likely Bugs/Memory Management/PointerOverflow/test.cpp

@@ -0,0 +1,42 @@
+struct P { int a, b; };
+bool check_pointer_overflow(P *ptr) {
+    // x86-64 gcc 9.2 -O2: deleted
+    // x86-64 clang 9.9.9 -O2: deleted
+    // x64 msvc v19.22 /O2: not deleted
+    return ptr + 0x12345678 < ptr; // BAD
+}
+bool check_pointer_overflow(P *ptr, P *ptr_end) {
+    // x86-64 gcc 9.2 -O2: not deleted
+    // x86-64 clang 9.0.0 -O2: not deleted
+    // x64 msvc v19.22 /O2: not deleted
+    return ptr_end - ptr > 4; // GOOD
+}
+
+struct Q {
+	#define Q_SIZE 32
+	char arr[Q_SIZE];
+	char *begin() { return &arr[0]; }
+	char *end() { return &arr[Q_SIZE]; }
+};
+
+void foo(int untrusted_int) {
+	Q q;
+    if (q.begin() + untrusted_int > q.end() || // GOOD (for the purpose of this test)
+          q.begin() + untrusted_int < q.begin()) // BAD [NOT DETECTED]
+      throw q;
+}
+
+typedef unsigned long size_t;
+
+bool not_in_range_bad(Q *ptr, Q *ptr_end, size_t a) {
+    return ptr + a >= ptr_end || // GOOD (for the purpose of this test)
+        ptr + a < ptr; // BAD
+}
+
+bool not_in_range_good(Q *ptr, Q *ptr_end, size_t a) {
+    return a >= ptr_end - ptr; // GOOD
+}
+
+bool in_range(Q *ptr, Q *ptr_end, size_t a) {
+    return a < ptr_end - ptr; // GOOD
+}