t5304: move prune -h test from t1517

t1517 is now focused on testing subcommands outside a repository.
Move the in-repo `-h` test for `prune` to t5304, which covers
this command.

Suggested-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Usman Akinyemi <usmanakinyemi202@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: Unique-Usman

t/t1517-outside-repo.sh

@@ -107,13 +107,6 @@ test_expect_success LIBCURL 'remote-http outside repository' '
 	test_grep "^error: remote-curl" actual
 '
 
-test_expect_success 'prune does not crash with -h' '
-	test_expect_code 129 git prune -h >usage &&
-	test_grep "[Uu]sage: git prune " usage &&
-	test_expect_code 129 nongit git prune -h >usage &&
-	test_grep "[Uu]sage: git prune " usage
-'
-
 for cmd in $(git --list-cmds=main)
 do
 	cmd=${cmd%.*} # strip .sh, .perl, etc.

t/t5304-prune.sh

@@ -364,4 +364,9 @@ test_expect_success 'gc.recentObjectsHook' '
 	git cat-file -p $BLOB
 '
 
+test_expect_success 'prune does not crash with -h' '
+	test_expect_code 129 git prune -h >usage &&
+	test_grep "[Uu]sage: git prune " usage
+'
+
 test_done