Simplify exit code logic

Co-authored-by: Arthur Baars <aibaars@github.com>

Author: hvitved

csharp/tools/autobuild.cmd

@@ -4,4 +4,4 @@ rem The autobuilder is already being traced
 set CODEQL_AUTOBUILDER_CSHARP_NO_INDEXING=true
 
 type NUL && "%CODEQL_EXTRACTOR_CSHARP_ROOT%/tools/%CODEQL_PLATFORM%/Semmle.Autobuild.CSharp.exe"
-IF %ERRORLEVEL% NEQ 0 exit /b %ERRORLEVEL%
+exit /b %ERRORLEVEL%