tests/std: Failing asserts emit assertion dialog boxes

[StephanTLavavej]

When a test in tests/std (or tests/tr1, presumably) fails an assert, it pops up a dialog box saying:

---------------------------
Microsoft Visual C++ Runtime Library
---------------------------
Debug Error!
Program: ...\tests\std\tests\P0218R1_filesystem\04\P0218R1_filesystem.exe
abort() has been called
(Press Retry to debug the application)
---------------------------
Abort   Retry   Ignore   
---------------------------

This is annoying when a dozen configurations of a single test are failing, and catastrophic when many tests are failing.

In libcxx, I solved this by force-including the AssertionDialogAvoider:

https://github.com/llvm/llvm-project/blob/e39c7ab2b9c39acc9e793fdfe5d531cef6798743/libcxx/test/support/msvc_stdlib_force_include.h#L31-L41

Can we do something similar for tests/std and tests/tr1?