Enable unit tests in libstd and libextra on Windows

[vadimcn]

Some of the tests are failing. I've only managed to fix 'memory_map_file', the rest are up for grabs...

Fixes #5261.

[sanxiyn]

Does it make sense to change check-fast to run std and extra tests? I thought check-fast was an alternative way to run rpass tests.

[vadimcn]

My understanding is that make check-fast is supposed to be a faster version of make check on platform(s) where process spawning is expensive. However, because of broken stack unwinding on Windows, only rpass tests were possible to be run in this way. This is no longer the case, and I'm trying to expand test coverage on Windows.

[brson]

@sanxiyn From my perspective 'check-fast' is just the target we use on the windows bots, so if there are tests we want to run there then it's fine to include them.

[sanxiyn]

@brson Shouldn't we rename the target to check-windows then?

[pnkfelix]

Assuming this lands, it sounds like it will fix #5261 (at least partially, maybe not enough to close the ticket...)

I don't know if I would want to rename check-fast to check-windows. It might go away anyhow: maybe we'll adopt a different strategy e.g. dynamic loading (#458, #7027, #7095), and then remove it (#4193)

[pnkfelix]

Also, regarding renaming check-fast to check-windows, there is active discussion of making not windows-specific; e.g. see Sully's suggestion on #8456.

[vadimcn]

Hmm, I don't think I've changed any non-windows code. Is there a way to get a callstack or something?