Add an `llvm::OStream` workalike class for use with `Logger::cout()`, with the crucial difference being special handling of `llvm::Type`s so they get printed by name rather than printing their full representation (which can be positively *huge*). This allows re-enabling some logger calls that were disabled due to extreme verbosity.

6cffbfff0363a122e6742fe5083d330519224b6b 0.9
a6dfd3cb5b99a10d3917bd8ed87d844ac2975a62 0.9.1