Add diagnostics for min/max algorithms when a InputIterator is used.

These algorithms require a ForwardIterator or better. Ensure
we diagnose the contract violation at compile time instead of
of silently doing the wrong thing.

Further algorithms will be audited in upcoming patches.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@340426 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed