[libc++] Update the list of symbols exported from libc++abi for new/delete

[libc++] Update the list of symbols exported from libc++abi for new/delete

When libc++ does not provide new/delete, libc++abi now also provides the
aligned allocation and deallocation functions, so those should be part of
the re-export list for libc++.

llvm-svn: 356804