correct names for `#[no_send]`/`#[no_freeze]` tests
Remove support for older CrateMap versions
clean up the `Rc`/`RcMut` types and move to libstd
auto merge of #9794 : thestinger/rust/rc, r=alexcrichton

I've left out a way to construct from a `Send` type until #9509 is resolved. I am confident that this interface can remain backwards compatible though, assuming we name the `Pointer` trait method `borrow`.

When there is a way to convert from `Send` (`from_send`), a future RAII-based `Mut` type can be used with this to implemented a mutable reference-counted pointer. For now, I've left around the `RcMut` type but it may drastically change or be removed.
auto merge of #9809 : fhahn/rust/remove-old-cratemap-code, r=alexcrichton

This patch removes the code responsible for handling older CrateMap versions (as discussed during #9593). Only the new (safer) layout is supported now.
rustpkg: Set exit codes properly and make tests take advantage of that

When I started writing the rustpkg tests, task failure didn't set the
exit code properly. But bblum's work from July fixed that. Hooray! I
just didn't know about it till now.

So, now rustpkg uses exit codes in a more conventional way, and some of
the tests are simpler.

The bigger issue will be to make task failure propagate the error message.
Right now, rustpkg does most of the work in separate tasks, which means if
a task fails, rustpkg can't distinguish between different types of failure
(see #3408)