Scripting: Fix regression from #1118

The new check-for-number behavior of Lua arguments broke
users who use large strings of just integers.

The Lua number check would convert the string to a number, but
that breaks user data because
Lua numbers have limited precision compared to an arbitrarily
precise number wrapped in a string.

Regression fixed and new test added.

Fixes #1118 again.

tests/unit/scripting.tcl

@@ -347,6 +347,13 @@ start_server {tags {"scripting"}} {
               return redis.call("get","foo")
         } 0
     } {9007199254740991}
+
+    test {String containing number precision test (regression of issue #1118)} {
+        r eval {
+            redis.call("set", "key", "12039611435714932082")
+            return redis.call("get", "key")
+        } 0
+    } {12039611435714932082}
 }
 
 # Start a new server since the last test in this stanza will kill the