RFR: 8253089: Windows (MSVC 2017) build fails after JDK-8243208

[Kim Barrett]

> On Sep 14, 2020, at 12:05 PM, Kim Barrett <kim.barrett at oracle.com> wrote:
> Note that it might be that such a limited warning disable is insufficient in
> the long run. This seems like a problem that might arise in other places as
> we make more use of constexpr. We might instead need to globally disable
> that warning for some limited range of VS versions.

Looks like I was right about that.  I’ve privately received a report of a similar problem
arising as a result of yesterday’s push of 8238956.  (I expect a bug report to be showing up
shortly.)

This will be a constant threat when adding uses of constexpr.

I think the only plausible solution is to disable that warning for VS versions prior to the one that fixes
that bug (mentioned in the referenced bug report).  I also think the change for 8253089 should be
reverted.

I don’t know why I never encountered this in my experiments with C++14 over the past more than
a year.  We (Oracle) only upgraded to VS2019 relatively recently (a few months).  Though I think
the I wrote the unit test that failed to build (in that private report) fairly recently, probably after we
switched over to VS2019.