[libc++] Revert the addition of map/multimap CTAD

This was found to be broken on Clang trunk. This is a revert of the
following commits (the subsequent commits added XFAILs to the tests
that were missing from the original submission):

    r362986: Implement deduction guides for map/multimap.
    r363014: Add some XFAILs
    r363097: Add more XFAILs
    r363197: Add even more XFAILs

llvm-svn: 363688