[Issue 21053] Test Suite run.d is built with compiler under test, must be build with bootstrap dmd

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21053

--- Comment #4 from Walter Bright <bugzilla at digitalmars.com> ---
(In reply to moonlightsentinel from comment #2)
> Partially, it's done for all CI which have an appropriatly recent host
> compiler, otherwise it falls back to the generated dmd. This affects a few
> CI machines which will update to an appropriate compiler eventually once we
> raise the minimally required bootstrap version.

Why can't simply the previous release be used?

After all, recent experience shows that using the compiler under test makes for
a very time consuming and miserable debugging experience, since run.d manages
to use all of Phobos and every feature in D :-/

I.e. it requires everything, Phobos and all, to be working before it can run a
single test.

Either that, or simply supply a pre-built known-working executable to be used
to drive the tests.

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