Problem: Vim9: "exit_cb" causes Vim to exit.
Solution: Require white space after a command in Vim9 script. (closesvim/vim#7467)
Also fix that Vim9 style heredoc was not always recognized.
b5b9480ee9
Omit EX_NONWHITE_OK, E1143, E1144: Vim9 script only.
Cherry-pick test_vimscript.vim changes from patch 8.2.2141.
Cherry-pick E1145 tag from Vim runtime.
N/A patches for version.c:
vim-patch:8.2.2140: build failure with tiny features
Problem: Build failure with tiny features.
Solution: Add #ifdef.
2a3cd3af45
Co-authored-by: Bram Moolenaar <Bram@vim.org>