patch 8.2.1572: Vim9: expand() does not take "true" as argument

Problem:    Vim9: expand() does not take "true" as argument.
Solution:   Use tv_get_bool_chk().  (closes #6819)

src/evalfunc.c

@@ -2434,7 +2434,7 @@ f_expand(typval_T *argvars, typval_T *rettv)
     rettv->v_type = VAR_STRING;
     if (argvars[1].v_type != VAR_UNKNOWN
 	    && argvars[2].v_type != VAR_UNKNOWN
-	    && tv_get_number_chk(&argvars[2], &error)
+	    && tv_get_bool_chk(&argvars[2], &error)
 	    && !error)
 	rettv_list_set(rettv, NULL);
 
@@ -2458,7 +2458,7 @@ f_expand(typval_T *argvars, typval_T *rettv)
 	// When the optional second argument is non-zero, don't remove matches
 	// for 'wildignore' and don't put matches for 'suffixes' at the end.
 	if (argvars[1].v_type != VAR_UNKNOWN
-				    && tv_get_number_chk(&argvars[1], &error))
+				    && tv_get_bool_chk(&argvars[1], &error))
 	    options |= WILD_KEEP_ALL;
 	if (!error)
 	{

src/testdir/test_vim9_func.vim

@@ -1497,6 +1497,12 @@ def Test_count()
   assert_equal(0, count('ABC ABC ABC', 'b', false))
 enddef
 
+def Test_expand()
+  split SomeFile
+  assert_equal(['SomeFile'], expand('%', true, true))
+  close
+enddef
+
 def Test_recursive_call()
   assert_equal(6765, Fibonacci(20))
 enddef

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1572,
 /**/
     1571,
 /**/