cbmc-cpp/Array4 test now works

This test passes as intended, and is no longer KNOWNBUG.

Author: kroening

regression/cbmc-cpp/Array4/test.desc

@@ -1,6 +1,7 @@
-KNOWNBUG
+CORE
 main.cpp
---bounds-check --pointer-check
+elsewhere.cpp
+^\[elsewhere\.array_bounds\.1\] line 7 array 'my_string' upper bound in my_string\[.*10\]: FAILURE$
 ^EXIT=10$
 ^SIGNAL=0$
 ^VERIFICATION FAILED$