patch 8.2.2650: Vim9: command modifiers not handled in nested function

Problem:    Vim9: command modifiers not handled in nested function.
Solution:   Keep function-local info in a structure and save it on the stack.

Author: brammool

src/testdir/test_vim9_func.vim

@@ -2363,6 +2363,29 @@ def Test_cmdmod_silent_restored()
   delete(fname)
 enddef
 
+def Test_cmdmod_silent_nested()
+  var lines =<< trim END
+      vim9script
+      var result = ''
+
+      def Error()
+          result ..= 'Eb'
+          eval [][0]
+          result ..= 'Ea'
+      enddef
+
+      def Crash()
+          result ..= 'Cb'
+          sil! Error()
+          result ..= 'Ca'
+      enddef
+
+      Crash()
+      assert_equal('CbEbEaCa', result)
+  END
+  CheckScriptSuccess(lines)
+enddef
+
 def Test_dict_member_with_silent()
   var lines =<< trim END
       vim9script

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2650,
 /**/
     2649,
 /**/

src/vim9.h

@@ -402,12 +402,14 @@ struct dfunc_S {
 // - ec_dfunc_idx:   function index
 // - ec_iidx:        instruction index
 // - ec_outer:	     stack used for closures
+// - funclocal:	     function-local data
 // - ec_frame_idx:   previous frame index
 #define STACK_FRAME_FUNC_OFF 0
 #define STACK_FRAME_IIDX_OFF 1
 #define STACK_FRAME_OUTER_OFF 2
-#define STACK_FRAME_IDX_OFF 3
-#define STACK_FRAME_SIZE 4
+#define STACK_FRAME_FUNCLOCAL_OFF 3
+#define STACK_FRAME_IDX_OFF 4
+#define STACK_FRAME_SIZE 5
 
 
 #ifdef DEFINE_VIM9_GLOBALS