patch 8.2.4375: ctx_imports is not used

Problem:    ctx_imports is not used.
Solution:   Delete ctx_imports.  Add missing dependency.

src/vim9.h

@@ -691,7 +691,7 @@ typedef struct {
 } lhs_T;
 
 /*
- * Context for compiling lines of Vim script.
+ * Context for compiling lines of a :def function.
  * Stores info about the local variables and condition stack.
  */
 struct cctx_S {
@@ -710,8 +710,6 @@ struct cctx_S {
     int		ctx_has_closure;    // set to one if a closure was created in
 				    // the function
 
-    garray_T	ctx_imports;	    // imported items
-
     skip_T	ctx_skip;
     scope_T	*ctx_scope;	    // current scope, NULL at toplevel
     int		ctx_had_return;	    // last seen statement was "return"