Scripting test: check that Lua can call commands rewirting argv.

SPOP, tested in the new test, is among the commands rewritng the
client->argv argument vector (it gets rewritten as SREM) for command
replication purposes.

Because of recent optimizations to client->argv caching in the context
of the Lua internal Redis client, it is important to test for SPOP to be
callable from Lua without bad effects to the other commands.

tests/unit/scripting.tcl

@@ -311,8 +311,21 @@ start_server {tags {"scripting"}} {
         r config set slave-read-only yes
         r slaveof 127.0.0.1 0
         r debug loadaof
-        r get foo
+        set res [r get foo]
+        r slaveof no one
+        set res
     } {102}
+
+    test {We can call scripts rewriting client->argv from Lua} {
+        r del myset
+        r sadd myset a b c
+        r mset a 1 b 2 c 3 d 4
+        assert {[r spop myset] ne {}}
+        assert {[r spop myset] ne {}}
+        assert {[r spop myset] ne {}}
+        assert {[r mget a b c d] eq {1 2 3 4}}
+        assert {[r spop myset] eq {}}
+    }
 }
 
 # Start a new server since the last test in this stanza will kill the