swift234

[Sema] Limit inout capture to @noescape contexts

The following diagnostics have been added:

1. implicit capture of inout arguments by closure literals that may escape (
   not mark by @noescape) is now invalid. This also includes implicit capture
   of `self`.
2. nested functions with inout captures cannot be used as arguments not marked
   @noescape.
3. nested function with inout captures cannot be a return value.

This change eliminates the need for the shadowing mechanism created for inouts.