The current approach has several problems:
- Types that are not inout types but loadable may incorrectly get
marked as inout types.
- When inout arguments get inlined or otherwise optimized LLDB cannot
rely on the type to decide to dereference that value.
- One argument may get represented by different types in the same
function depending on what code is generated for it.
Fixes rdar://problem/rdar://problem/39023374
