t: add test for git refs list subcommand

Adapt `t/t6300-for-each-ref.sh` to invoke ${GIT_REFS_LIST_CMD},
defaulting to `for-each-ref` if the variable is unset.

Add `t/t1461-refs-list.sh` to test git refs list by setting
`GIT_REFS_LIST_CMD` to `refs list` and sourcing
`t/t6300-for-each-ref.sh`

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: shejialuo <shejialuo@gmail.com>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Meet Soni <meetsoni3017@gmail.com>

Author: inosmeet

t/meson.build

@@ -224,6 +224,7 @@ integration_tests = [
   't1450-fsck.sh',
   't1451-fsck-buffer.sh',
   't1460-refs-migrate.sh',
+  't1461-refs-list.sh',
   't1500-rev-parse.sh',
   't1501-work-tree.sh',
   't1502-rev-parse-parseopt.sh',

t/t1461-refs-list.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+test_description='git refs list tests'
+
+. ./test-lib.sh
+
+GIT_REFS_LIST_CMD='refs list'
+. "$TEST_DIRECTORY"/t6300-for-each-ref.sh