selftests: core: include linux/close_range.h for CLOSE_RANGE_* macros

Correct header file is needed for getting CLOSE_RANGE_* macros. 
Previously it was tested with newer glibc which didn't show the need to
include the header which was a mistake.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: ec54424 ("selftests: core: remove duplicate defines")
Reported-by: Aishwarya TCV <[email protected]>
Link: https://lore.kernel.org/all/[email protected]
Signed-off-by: Muhammad Usama Anjum <[email protected]>
Cc: Shuah Khan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: musamaanjum

tools/testing/selftests/core/close_range_test.c

@@ -12,6 +12,7 @@
 #include <syscall.h>
 #include <unistd.h>
 #include <sys/resource.h>
+#include <linux/close_range.h>
 
 #include "../kselftest_harness.h"
 #include "../clone3/clone3_selftests.h"