tests: check decoding of utimes syscall

* tests/utimes.c: New file.
* tests/utimes.test: New test.
* tests/.gitignore: Add utimes.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add utimes.test.
diff --git a/tests/.gitignore b/tests/.gitignore
index bcbf695..c7db886 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -235,6 +235,7 @@
 userfaultfd
 utime
 utimensat
+utimes
 vfork-f
 vmsplice
 wait