fetch-pack: test explicitly that --all can fetch tag references pointing to non-commits

fetch-pack: test explicitly that --all can fetch tag references pointing to non-commits

Fetch-pack --all became broken with respect to unusual tags in
5f0fc64513 (fetch-pack: eliminate spurious error messages, 2012-09-09),
and was fixed only recently in e9502c0a7f (fetch-pack: don't try to fetch
peel values with --all, 2018-06-11). However the test added in
e9502c0a7f does not explicitly cover all funky cases.

In order to be sure fetching funky tags will never break, let's
explicitly test all relevant cases with 4 tag objects pointing to 1) a
blob, 2) a tree, 3) a commit, and 4) another tag objects. The referenced
tag objects themselves are referenced from under regular refs/tags/*
namespace. Before e9502c0a7f `fetch-pack --all` was failing e.g. this way:

        .../git/t/trash directory.t5500-fetch-pack/fetchall$ git ls-remote ..
        44085874...        HEAD
        ...
        bc4e9e1f...        refs/tags/tag-to-blob
        038f48ad...        refs/tags/tag-to-blob^{}	# peeled
        520db1f5...        refs/tags/tag-to-tree
        7395c100...        refs/tags/tag-to-tree^{}	# peeled

        .../git/t/trash directory.t5500-fetch-pack/fetchall$ git fetch-pack --all ..
        fatal: A git upload-pack: not our ref 038f48ad...
        fatal: The remote end hung up unexpectedly

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>