Refactor the hardcoded formatters facility to use sequences of lambdas - still no feature change as none are present now, but this feels cleaner. Also, hardcoded formatters do not need to be per-type, so disable caching thereof

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@216004 91177308-0d34-0410-b5e6-96231b3b80d8