r260553 added a number of mangled C++ symbols to Version.map inside of
an existing `extern "C++"` block.
ld.bfd 2.17.50 treats `extern "C++"` permissively and will match both
mangled and demangled symbols against the strings in the version map
block. ld.lld interprets `extern "C++"` strictly, and matches only
demangled symbols.
I believe lld's behaviour is correct. Contemporary versions of ld.bfd
also behave as lld does, so move the mangled symbols out of the
`extern "C++"` block.
PR: 225128, 185663
MFC after: 1 week
Sponsored by: The FreeBSD Foundation