vim-patch:8.0.0184: fix ex-mode exit code #7943

Problem:    When in Ex mode and an error is caught by try-catch, Vim still
            exits with a non-zero exit code.
Solution:   Don't set ex_exitval when inside a try-catch. (partly by Christian
            Brabandt)

2b7bc567b9

src/nvim/message.c

@@ -487,9 +487,6 @@ int emsg(const char_u *s_)
   }
 
   called_emsg = true;
-  if (emsg_silent == 0) {
-    ex_exitval = 1;
-  }
 
   // If "emsg_severe" is TRUE: When an error exception is to be thrown,
   // prefer this message over previous messages for the same command.
@@ -540,6 +537,8 @@ int emsg(const char_u *s_)
       return true;
     }
 
+    ex_exitval = 1;
+
     // Reset msg_silent, an error causes messages to be switched back on.
     msg_silent = 0;
     cmd_silent = FALSE;