Apply suggestions from code review

Co-authored-by: Stephen Toub <[email protected]>

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

@@ -502,8 +502,8 @@ private bool ForkAndExecProcess(
         {
             if (string.IsNullOrEmpty(resolvedFilename))
             {
-                int errno = Interop.Error.ENOENT.Info().RawErrno;
-                throw CreateExceptionForErrorStartingProcess(GetErrorMessage(errno), errno, startInfo.FileName, cwd);
+                Interop.ErrorInfo errno = Interop.Error.ENOENT.Info();
+                throw CreateExceptionForErrorStartingProcess(errno.GetErrorMessage(), errno.RawErrno, startInfo.FileName, cwd);
             }
 
             // Lock to avoid races with OnSigChild
@@ -550,7 +550,7 @@ private bool ForkAndExecProcess(
                         return false;
                     }
 
-                    throw CreateExceptionForErrorStartingProcess(GetErrorMessage(errno), errno, resolvedFilename, cwd);
+                    throw CreateExceptionForErrorStartingProcess(new ErrorInfo(errno).GetErrorMessage(), errno, resolvedFilename, cwd);
                 }
             }
             finally
@@ -1106,7 +1106,5 @@ private static int OnSigChild(int reapAll, int configureConsole)
                 s_processStartLock.ExitWriteLock();
             }
         }
-
-        private static string GetErrorMessage(int error) => Interop.Sys.StrError(error);
     }
 }