Add negative tests for context API functions (#2494)

This PR adds negative tests for the following API functions:

- clCreateContext
- clCreateContextFromType
- clRetainContext
- clReleaseContext
- clSetContextDestructorCallback

Also, define a new macro `test_object_failure_ret` to test for an
expected error code and the returned object is `NULL` as a result of a
failure.

Signed-off-by: Michael Rizkalla <michael.rizkalla@arm.com>

test_common/harness/errorHelpers.h

@@ -120,6 +120,12 @@ static int vlog_win32(const char *format, ...);
             return retValue;                                                   \
         }                                                                      \
     }
+#define test_object_failure_ret(object, errCode, expectedErrCode, msg,         \
+                                retValue)                                      \
+    {                                                                          \
+        test_assert_error_ret(object == nullptr, msg, retValue);               \
+        test_failure_error_ret(errCode, expectedErrCode, msg, retValue);       \
+    }
 #define print_failure_error(errCode, expectedErrCode, msg)                     \
     log_error("ERROR: %s! (Got %s, expected %s from %s:%d)\n", msg,            \
               IGetErrorString(errCode), IGetErrorString(expectedErrCode),      \