patch 8.2.3833: error from term_start() not caught by try/catch

Problem:    Error from term_start() not caught by try/catch.
Solution:   save and restore did_emsg when applying autocommands. (Ozaki
            Kiichi, closes #9361)

src/autocmd.c

@@ -1891,6 +1891,7 @@ apply_autocmds_group(
     int		did_save_redobuff = FALSE;
     save_redo_T	save_redo;
     int		save_KeyTyped = KeyTyped;
+    int		save_did_emsg;
     ESTACK_CHECK_DECLARATION
 
     /*
@@ -2171,9 +2172,13 @@ apply_autocmds_group(
 	    // make sure cursor and topline are valid
 	    check_lnums(TRUE);
 
+	save_did_emsg = did_emsg;
+
 	do_cmdline(NULL, getnextac, (void *)&patcmd,
 				     DOCMD_NOWAIT|DOCMD_VERBOSE|DOCMD_REPEAT);
 
+	did_emsg += save_did_emsg;
+
 	if (nesting == 1)
 	    // restore cursor and topline, unless they were changed
 	    reset_lnums();

src/testdir/test_terminal3.vim

@@ -901,5 +901,25 @@ func Test_terminal_getwinpos()
   only!
 endfunc
 
+func Test_terminal_term_start_error()
+  func s:term_start_error() abort
+    try
+      return term_start([[]])
+    catch
+      return v:exception
+    finally
+      "
+    endtry
+  endfunc
+  autocmd WinEnter * call type(0)
+
+  " Must not crash in s:term_start_error, nor the exception thrown.
+  let result = s:term_start_error()
+  call assert_match('^Vim(return):E730:', result)
+
+  autocmd! WinEnter
+  delfunc s:term_start_error
+endfunc
+
 
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -749,6 +749,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3833,
 /**/
     3832,
 /**/