vim: Import v8.1.1312

* 8.1.1312: Coverity warning for using uninitialized variable
* 8.1.1311: aborting an autocmd with an exception is not tested
* 8.1.1310: named function arguments are never optional
* 8.1.1309: test for Normal highlight fails on MS-Windows GUI
* 8.1.1308: the Normal highlight is not defined when compiled with GUI
* Update runtime files
* 8.1.1307: cannot reconnect to the X server after it restarted
* 8.1.1306: Borland support is outdated and doesn't work
* 8.1.1305: there is no easy way to manipulate environment variables
* 8.1.1304: MS-Windows: compiler warning for unused value
* 8.1.1303: not possible to hide a balloon

gitlog.txt

@@ -1 +1 @@
-* [8.1.1302](https://github.com/vim/vim/releases/tag/v8.1.1302): v:beval_text is not tested in Visual mode\n* [8.1.1301](https://github.com/vim/vim/releases/tag/v8.1.1301): when compiled with VIMDLL some messages are not shown\n* [8.1.1300](https://github.com/vim/vim/releases/tag/v8.1.1300): in a terminal 'ballooneval' does not work right away\n* [8.1.1299](https://github.com/vim/vim/releases/tag/v8.1.1299): "extends" from 'listchars' is used when 'list' is off\n* [8.1.1298](https://github.com/vim/vim/releases/tag/v8.1.1298): invalid argument test fails without X clipboard\n* [8.1.1297](https://github.com/vim/vim/releases/tag/v8.1.1297): invalid argument test fails without GTK\n* [8.1.1296](https://github.com/vim/vim/releases/tag/v8.1.1296): crash when using invalid command line argument
+* [8.1.1312](https://github.com/vim/vim/releases/tag/v8.1.1312): Coverity warning for using uninitialized variable\n* [8.1.1311](https://github.com/vim/vim/releases/tag/v8.1.1311): aborting an autocmd with an exception is not tested\n* [8.1.1310](https://github.com/vim/vim/releases/tag/v8.1.1310): named function arguments are never optional\n* [8.1.1309](https://github.com/vim/vim/releases/tag/v8.1.1309): test for Normal highlight fails on MS-Windows GUI\n* [8.1.1308](https://github.com/vim/vim/releases/tag/v8.1.1308): the Normal highlight is not defined when compiled with GUI\n* Update runtime files\n* [8.1.1307](https://github.com/vim/vim/releases/tag/v8.1.1307): cannot reconnect to the X server after it restarted\n* [8.1.1306](https://github.com/vim/vim/releases/tag/v8.1.1306): Borland support is outdated and doesn't work\n* [8.1.1305](https://github.com/vim/vim/releases/tag/v8.1.1305): there is no easy way to manipulate environment variables\n* [8.1.1304](https://github.com/vim/vim/releases/tag/v8.1.1304): MS-Windows: compiler warning for unused value\n* [8.1.1303](https://github.com/vim/vim/releases/tag/v8.1.1303): not possible to hide a balloon