MAINT-1175: Reimplement LLTypeInfoLookup for better lookup failure. The original LLTypeInfoLookup implementation was based on two assumptions: small overall container size, and infrequent normal-case lookup failures. Those assumptions led to binary-searching a sorted vector, with linear search as a fallback to cover the problem case of two different type_info* values for the same type. As documented in the Jira, this turned out to be a problem. The container size was larger than expected, and failed lookups turned out to be far more common than expected. The new implementation is based on a hash map of std::type_info::name() strings, which should perform equally well in the success and failure cases: no special-case fallback logic.