Add publictests test checker to druntime (reboot of #2087)

[MoonlightSentinel]

Checking public examples is always worthwhile IMHO.

• Update libdparse dependency of test_extractor.d tools#402
• Fix #390 - Error for opaque enum with base type dlang-community/libdparse#391
• Fix #397 - extern(C++, ...) only supports identifiers dlang-community/libdparse#398
• Handle empty doc comments ("///") on unittests dlang-community/libdparse#401
• Accept this as an asm operand dlang-community/libdparse#402
• Fix #53 - Support GDC extended asm syntax dlang-community/libdparse#404 (optional)
• Remove unused code from test_extractor.d tools#403
• Update libdparse used by test_extractor.d to include latest bugfixes

[wilzbach]

Just as an FYI this won't apply to all existing PRs. They need to be rebased for them to have this test.

[wilzbach]

Thank you very much!!!

[dlang-bot]

Thanks for your pull request and interest in making D better, @MoonlightSentinel! We are looking forward to reviewing it, and you should be hearing from a maintainer soon.
Please verify that your PR follows this checklist:

• My PR is fully covered with tests (you can see the coverage diff by visiting the details link of the codecov check)
• My PR is as minimal as possible (smaller, focused PRs are easier to review than big ones)
• I have provided a detailed rationale explaining my changes
• New or modified functions have Ddoc comments (with Params: and Returns:)

Please see CONTRIBUTING.md for more information.

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Bugzilla references

Your PR doesn't reference any Bugzilla issue.

If your PR contains non-trivial changes, please reference a Bugzilla issue or create a manual changelog.

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + druntime#3069"

[MoonlightSentinel]

Rebased to retrigger the CI

[MoonlightSentinel]

Not sure why Win32 reliably fails on Azure & auto-tester as this doesn't touch windows specific stuff. Anybody got an idea?

[MoonlightSentinel]

Nevermind, it's an Optlink error that opens a dialog ...

Unexpected OPTLINK Termination at EIP=004211CB

EDIT: Apparently triggered by 202a46c

[MoonlightSentinel]

Using fabs instead of an explicit expressions seems to work.

Ping @wilzbach