vm: fix double VM run from CLI

Fixes one more instruction being ran when VM FAULTs:

NEO-GO-VM > run
NEO-GO-VM > error encountered at instruction 6 (ROLL)
NEO-GO-VM > runtime error: invalid memory address or nil pointer dereference
FAULT
NEO-GO-VM > error encountered at instruction 7 (SETITEM)
NEO-GO-VM > interface conversion: interface {} is []vm.StackItem, not []uint8

Refs. #96.

pkg/vm/cli/cli.go

@@ -127,16 +127,13 @@ func (c *VMCLI) handleCommand(cmd string, args ...string) {
 		fmt.Printf("READY: loaded %d instructions\n", c.vm.Context().LenInstr())
 
 	case "run":
+		if len(args) != 0 {
 			var (
 				method []byte
 				params []vm.StackItem
 				err    error
 				start  int
 			)
-
-		if len(args) == 0 {
-			c.vm.Run()
-		} else {
 			if isMethodArg(args[0]) {
 				method = []byte(args[0])
 				start = 1
@@ -146,8 +143,8 @@ func (c *VMCLI) handleCommand(cmd string, args ...string) {
 				fmt.Println(err)
 				return
 			}
-		}
 			c.vm.LoadArgs(method, params)
+		}
 		c.vm.Run()
 
 	case "cont":