microsoft/STL's libcxx/skipped_tests.txt is now available

Hi libcxx devs,

For almost 4 years, MSVC's STL has been running libcxx's test suite (with both the MSVC compiler and Clang) which has been enormously helpful for testing new features and finding conformance issues - we really appreciate your work.

We use llvm-project's sources, unmodified, but we maintain a list of tests that need to be skipped due to missing features, MSVC compiler/library bugs, environment incompatibilities, and problems in the libcxx tests themselves. We've reported instances of the last category over the years (and many have been fixed). I thought you'd like to know that our list of skipped tests is now publicly available with short comments explaining our analysis of each issue:

https://github.com/microsoft/STL/blob/master/tests/libcxx/skipped_tests.txt

We hope that this will be useful (and we plan to continue submitting patches to fix conformance issues, along with fixing those MSVC bugs).

STL