Add `@autoclosure` to parameter flags associated with
function type metadata, which makes it possible to correctly
round-trip mangled name <-> metadata of function types which
have parameters marked as `@autoclosure`.
Resolves: rdar://problem/45489901
This ABI endpoint is used to retrieve metadata about functions
without parameters. Which is very common use-case and it
makes sense to save some code size for that.
Switch most general endpoint to be `flags, parameters, parameterFlags, result`,
instead of opaque `void **`, more specialized ones to use follow argument scheme:
`flags, param0, [flags0], ..., paramN, [flagsN], result` and store parameter/flags
information separately in `FunctionCacheEntry::{Key, Data}` as well.
Switch most general endpoint to be `flags, parameters, parameterFlags, result`,
instead of opaque `void **`, more specialized ones to use follow argument scheme:
`flags, param0, [flags0], ..., paramN, [flagsN], result` and store parameter/flags
information separately in `FunctionCacheEntry::{Key, Data}` as well.
This changes layout of the parameter metadata from single tuple record
(in case of materializable type) to N records each corresponding to
invididual function parameter, where functions with no parameters
`() -> Void` get 0 records allocated.
