Test MS_ constants on FreeBSD

Author: gnzlbg

libc-test/build.rs

@@ -1711,12 +1711,6 @@ fn test_freebsd(target: &str) {
             // FIXME: still required?
             "SIGUNUSED" => true, // removed in glibc 2.26
 
-            // weird signed extension or something like that?
-            // FIXME: still required?
-            "MS_NOUSER" => true,
-            // FIXME: still required?
-            "MS_RMT_MASK" => true, // updated in glibc 2.22 and musl 1.1.13
-
             // These constants were removed in FreeBSD 11 (svn r273250) but will
             // still be accepted and ignored at runtime.
             "MAP_RENAME" | "MAP_NORESERVE" => true,