undefined behavior "upcast of misaligned address" detected by UBSan w/wallet.send test

[androm3da]

SUMMARY: AddressSanitizer: undefined-behavior /usr/lib/gcc/x86_64-linux-gnu/5.4.0/../../../../include/c++/5.4.0/bits/stl_tree.h:1632:23 in 
/usr/lib/gcc/x86_64-linux-gnu/5.4.0/../../../../include/c++/5.4.0/bits/stl_tree.h:1910:28: runtime error: upcast of misaligned address 0x7ffc474864e8 for type 'std::_Rb_tree_node<std::pair<const boost::multiprecision::number<boost::multiprecision::backends::cpp_int_backend<128, 128, boost::multiprecision::cpp_integer_type::unsigned_magnitude, boost::multiprecision::cpp_int_check_type::unchecked, void>, boost::multiprecision::expression_template_option::et_off>, std::shared_ptr<rai::block> > >', which requires 16 byte alignment
0x7ffc474864e8: note: pointer points here
 fc 7f 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  e8 64 48 47 fc 7f 00 00  e8 64 48 47
              ^ 

[androm3da]

Might need to be blacklisted if it's a libstdc++ bug.

[cryptocode]

Known libstdc++ issue, fixed in 2015, see e.g. https://bugs.chromium.org/p/chromium/issues/detail?id=532101