swift234

Remove unfinished notion of "Component" (originally for resilience).

docs/Resilience.rst describes the notion of a resilience component:
if the current source file is in the same component as a module being
used, it can use fragile access for everything in the other module,
with the assumption that everything in a component will always be
recompiled together.

However, nothing is actually using this today, and the interface we
have is probably not what we'll want in 2.0, when we actually implement
resilience.

Swift SVN r9174