Update src/libraries/System.Diagnostics.Process/src/System/Diagnostic…

…s/Process.Unix.cs

Co-authored-by: Adam Sitnik <[email protected]>

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.Unix.cs

@@ -529,7 +529,7 @@ private bool ForkAndExecProcess(
                         return false;
                     }
 
-                    string directoryForException = cwd?.Length > 0 ? cwd : Directory.GetCurrentDirectory();
+                    string directoryForException = string.IsNullOrEmpty(cwd) ? Directory.GetCurrentDirectory() : cwd;
                     string msg = SR.Format(SR.FailedToStartFileDirectory, filename, directoryForException, GetErrorMessage(errno));
                     throw new Win32Exception(errno, msg);
                 }