Remove trailing zero words from Bitmapset

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Making empty Bitmapsets always be NULL ×

First at 2023-02-28 21:59:48 by Tom Lane <tgl at sss.pgh.pa.us>
Latest at 2023-07-04 11:24:08 by Yuya Watari <watari.yuya at gmail.com>
Latest attachment (remove_trailing_zero_words_from_bitmapsets_v5.patch) at 2023-07-03 00:09:48 from David Rowley <dgrowleyml at gmail.com>

    Attachment (remove_trailing_zero_words_from_bitmapsets_v5.patch) at 2023-07-03 00:09:48 from David Rowley <dgrowleyml at gmail.com> (Patch: Yes)
    Attachment (master_vs_v4_m2pro.png) at 2023-07-02 21:27:25 from David Rowley <dgrowleyml at gmail.com> (Patch: No)
    Attachment (figure.png) at 2023-06-30 02:10:25 from Yuya Watari <watari.yuya at gmail.com> (Patch: No)
    Attachment (bitmapset_tweaks_delta.patch.txt) at 2023-06-28 10:58:08 from David Rowley <dgrowleyml at gmail.com> (Patch: Yes)
    Attachment (profile-patch-for-master.txt) at 2023-06-27 09:11:14 from Yuya Watari <watari.yuya at gmail.com> (Patch: Yes)
    Attachment (plan_times.patch) at 2023-06-24 04:15:08 from David Rowley <dgrowleyml at gmail.com> (Patch: Yes)
    Attachment (remove_zero_trailing_words_from_bitmapsets_v4.patch) at 2023-06-20 04:16:56 from David Rowley <dgrowleyml at gmail.com> (Patch: Yes)
    Attachment (remove_zero_trailing_words_from_bitmapsets_v3.patch) at 2023-06-13 11:07:31 from David Rowley <dgrowleyml at gmail.com> (Patch: Yes)
    Attachment (v2-0001-Remove-trailing-zero-words-from-Bitmapsets.patch) at 2023-06-12 12:31:47 from Yuya Watari <watari.yuya at gmail.com> (Patch: Yes)
    Attachment (v2-0001-Remove-bms_is_empty_internal-function-calls.patch) at 2023-03-16 11:45:28 from Yuya Watari <watari.yuya at gmail.com> (Patch: Yes)
    Attachment (v1-0001-Remove-bms_is_empty_internal-function-calls.patch) at 2023-03-16 01:30:57 from Yuya Watari <watari.yuya at gmail.com> (Patch: Yes)
    Attachment (v1-0001-Remove-trailing-zero-words-from-Bitmapsets.patch) at 2023-03-07 04:06:42 from David Rowley <dgrowleyml at gmail.com> (Patch: Yes)
    Attachment (v1-make-struct-Bitmapset-private.patch) at 2023-03-03 22:08:32 from Tom Lane <tgl at sss.pgh.pa.us> (Patch: Yes)
    Attachment (bms_no_trailing_zero_words.patch) at 2023-03-03 01:52:22 from David Rowley <dgrowleyml at gmail.com> (Patch: Yes)
    Attachment (v2-0001-Remove-bms_first_member.patch) at 2023-03-01 22:59:45 from Tom Lane <tgl at sss.pgh.pa.us> (Patch: Yes)
    Attachment (v1-make-empty-bitmapsets-always-be-NULL.patch) at 2023-02-28 21:59:48 from Tom Lane <tgl at sss.pgh.pa.us> (Patch: Yes)