patch 8.2.1516: Vim9: error for :exe has wrong line number

Problem:    Vim9: error for :exe has wrong line number.
Solution:   Set line number before calling do_cmdline_cmd(). (closes #6774)

Author: brammool

src/testdir/test_vim9_script.vim

@@ -2159,8 +2159,9 @@ def Test_execute_cmd()
   echomsg [1, 2, 3] #{a: 1, b: 2}
   assert_match('^\[1, 2, 3\] {''a'': 1, ''b'': 2}$', Screenline(&lines))
 
-  call CheckDefFailure(['execute xxx'], 'E1001:')
-  call CheckDefFailure(['execute "cmd"# comment'], 'E488:')
+  call CheckDefFailure(['execute xxx'], 'E1001:', 1)
+  call CheckDefExecFailure(['execute "tabnext " .. 8'], 'E475:', 1)
+  call CheckDefFailure(['execute "cmd"# comment'], 'E488:', 1)
 enddef
 
 def Test_execute_cmd_vimscript()

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1516,
 /**/
     1515,
 /**/

src/vim9execute.c

@@ -1062,7 +1062,10 @@ call_def_function(
 		    if (ga.ga_data != NULL)
 		    {
 			if (iptr->isn_type == ISN_EXECUTE)
+			{
+			    SOURCING_LNUM = iptr->isn_lnum;
 			    do_cmdline_cmd((char_u *)ga.ga_data);
+			}
 			else
 			{
 			    msg_sb_eol();