patch 8.2.0098: exe stack length can be wrong without being detected

Problem:    Exe stack length can be wrong without being detected.
Solution:   Add a check when ABORT_ON_INTERNAL_ERROR is defined.

src/map.c

@@ -1918,10 +1918,12 @@ check_map_keycodes(void)
     int		abbr;
     int		hash;
     buf_T	*bp;
+    ESTACK_CHECK_DECLARATION
 
     validate_maphash();
     // avoids giving error messages
     estack_push(ETYPE_INTERNAL, (char_u *)"mappings", 0);
+    ESTACK_CHECK_SETUP
 
     // Do this once for each buffer, and then once for global
     // mappings/abbreviations with bp == NULL
@@ -1978,6 +1980,7 @@ check_map_keycodes(void)
 	if (bp == NULL)
 	    break;
     }
+    ESTACK_CHECK_NOW
     estack_pop();
 }