Adapt to switch to Clang for Windows host builds

Bug: http://b/69933068

Bug: http://b/91353691: std::chrono_utils is not available in the
libstdc++ in the mingw/gcc prebuilts.  They can be used once we switch
to using libc++ for Windows host.

Test: m native-host-cross with Clang
Change-Id: If9f0f1f201d5e4e445890075ad64c2d6086b0491