tests: adding sharded memcached test

Signed-off-by: Reto Achermann <achreto@gmail.com>

Author: achreto

kernel/tests/s10_benchmarks.rs

@@ -858,9 +858,9 @@ fn s10_memcached_benchmark_internal() {
         (16 * 1024 /* MB */, 16 /* MB */, 2000000, 300_000)
     } else {
         (
+            256 * 1024, /* MB */
             128 * 1024, /* MB */
-            32 * 1024,  /* MB */
-            50000000,
+            100_000_000,
             600_000,
         )
     };