patch 8.2.4270: generating nv_cmdidxs.h requires building Vim twice

Problem:    Generating nv_cmdidxs.h requires building Vim twice.
Solution:   Move the table into a separate file and use a separate executable
            to extract the command characters. (Ozaki Kiichi, closes #9669)
diff --git a/src/Make_vms.mms b/src/Make_vms.mms
index 0569054..f1689be 100644
--- a/src/Make_vms.mms
+++ b/src/Make_vms.mms
@@ -977,7 +977,7 @@
 normal.obj : normal.c vim.h [.auto]config.h feature.h os_unix.h \
  ascii.h keymap.h termdefs.h macros.h structs.h regexp.h \
  gui.h beval.h [.proto]gui_beval.pro option.h ex_cmds.h proto.h \
- errors.h globals.h nv_cmdidxs.h
+ errors.h globals.h nv_cmdidxs.h nv_cmds.h
 ops.obj : ops.c vim.h [.auto]config.h feature.h os_unix.h   \
  ascii.h keymap.h termdefs.h macros.h structs.h regexp.h gui.h beval.h \
  [.proto]gui_beval.pro option.h ex_cmds.h proto.h errors.h globals.h