Add lmdb regression tests to meson

[fredmorcos]

Short description

Add lmdb regression tests to meson

Checklist

I have:

• read the CONTRIBUTING.md document
• compiled this code
• tested this code
• included documentation (including possible behaviour changes)
• documented the code
• added or modified regression test(s)
• added or modified unit test(s)
• checked that this code was merged to master

[coveralls]

Pull Request Test Coverage Report for Build 11033932921

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 5509 unchanged lines in 73 files lost coverage.
• Overall coverage decreased (-3.4%) to 61.265%

---

Files with Coverage Reduction	New Missed Lines	%
pdns/webserver.hh	1	69.16%
pdns/recursordist/ext/protozero/include/protozero/config.hpp	1	0.0%
pdns/packethandler.cc	1	72.69%
modules/gpgsqlbackend/gpgsqlbackend.cc	1	88.62%
pdns/recursordist/sortlist.hh	1	75.0%
pdns/iputils.hh	1	76.65%
pdns/dnstap.cc	2	68.82%
ext/probds/murmur3.cc	2	88.24%
pdns/dnsdistdist/dnscrypt.cc	2	66.83%
pdns/recursordist/negcache.hh	2	88.24%

Totals
Change from base Build 11030373839:	-3.4%
Covered Lines:	119166
Relevant Lines:	162008

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💛 - Coveralls