The function is used by raft and fails with ubsan and clang.
The ub is harmless. Lets wait for it to be fixed in boost.
Message-Id: <20201109090353.GZ3722852@scylladb.com>
rapidjson has a harmless (but true) ubsan violation. It was fixed
in 16872af889.
Since rapidjson has't released since 2016, we're unlikely to see
the fix, so suppress it to prevent the tests failing. In any case
the violation is harmless.
gcc's ubsan doesn't object to the addition.
Closes#7357