ZTS: Replace MD5 and SHA256 wit XXH128

For data integrity checks as done in ZTS, the verification for
unintended data corruption with xxhash128 should be a lot faster
and perfectly usable.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes #16577

tests/zfs-tests/include/commands.cfg

@@ -100,7 +100,8 @@ export SYSTEM_FILES_COMMON='awk
     uniq
     vmstat
     wc
-    xargs'
+    xargs
+    xxh128sum'
 
 export SYSTEM_FILES_FREEBSD='chflags
     compress
@@ -112,13 +113,11 @@ export SYSTEM_FILES_FREEBSD='chflags
     jexec
     jls
     lsextattr
-    md5
     mdconfig
     newfs
     pw
     rmextattr
     setextattr
-    sha256
     showmount
     swapctl
     sysctl
@@ -146,7 +145,6 @@ export SYSTEM_FILES_LINUX='attr
     lscpu
     lsmod
     lsscsi
-    md5sum
     mkswap
     modprobe
     mountpoint
@@ -156,7 +154,6 @@ export SYSTEM_FILES_LINUX='attr
     perf
     setfattr
     setpriv
-    sha256sum
     udevadm
     unshare
     useradd