enforce "non-array trivial standard-layout" for string and string_view

[fsb4000]

Fixes #1261

I think libc++ tests the static_asserts: https://github.com/llvm/llvm-project/blob/master/libcxx/test/std/strings/basic.string/char.bad.fail.cpp and https://github.com/llvm/llvm-project/blob/master/libcxx/test/std/strings/string.view/char.bad.fail.cpp

How can I enable basic.string/char.bad.fail.cpp ? I did not find it among SKIPPED

[ghost]

All CLA requirements met.

[cbezault]

It's probably failing, just for the wrong reason. Upstream has the ability to parse errors coming out of clang to determine if the failure was for the correct reason. We just mark .fail.cpp tests as successful if they fail for any reason.

i.e. The test is already running so there's nothing you have to do.
Edit: I was wrong it was just marked as FAIL.

[StephanTLavavej]

Awesome, thanks for fixing this!