More informative output if onetest.cmd run singularly.

It was not intended that this cmd file be run separately. It is invoked by
alltest1.cmd which in turn is invoked by alltest.cmd. This 'chain' is
requierd to set up the appropriate environmnet variables.

test/onetest.cmd

@@ -13,6 +13,8 @@ REM
 @if "%TIDYOUT%." == "." goto Err3
 @if NOT EXIST %TIDYOUT%\nul goto Err4
 @if NOT EXIST input\nul goto Err5
+@if "%1x" == "x" goto Err8
+@if "%2x" == "x" goto Err9
 
 set TESTNO=%1
 set EXPECTED=%2
@@ -105,4 +107,13 @@ goto done
 @pause
 @goto done
 
+:Err8
+@echo.
+@echo ERROR: No input test number given!
+:Err9
+@echo ERROR: No expected exit value given!
+@echo.
+@goto done
+
+
 :done