Revert "simple test-fixture (#263)"

[edevil]

This reverts commit 101a34b.

This commit is currently breaking edgeworker tests.

external/workerd/src/workerd/tests/test-fixture.c++:215:17: error: no member named 'any_of' in namespace 'std'
    return std::any_of(errorsToIgnore.begin(), errorsToIgnore.end(), [&description](auto error) {
           ~~~~~^

[mikea]

Sorry for this. I wonder why didn't build catch it? looks like <algorithm> is included on some platforms and not others.

In any case, since this is still open, let's consider a trivial fix in #291

[jasnell]

Awesome, ok, will close in favor of #291