* main: (47 commits)
  Add core dump support to the runtime (bytecodealliance#6513)
  Resource table tracks child relationships (bytecodealliance#6779)
  Wasmtime: Move `OnDemandInstanceAllocator` to its own module (bytecodealliance#6790)
  wasi: Test the stdio streams implementation (bytecodealliance#6764)
  Don't generate same-named imports in fact modules (bytecodealliance#6783)
  Wasmtime: Add support for Wasm tail calls (bytecodealliance#6774)
  Cranelift: Fix `ABIMachineSpec::gen_add_imm` for riscv64 (bytecodealliance#6780)
  Update the wasm-tools family of crates, disallow empty component types (bytecodealliance#6777)
  Fix broken link to WASI API documentation (bytecodealliance#6775)
  A bunch of cleanups for cranelift-codegen-meta (bytecodealliance#6772)
  Implement component-to-component calls with resources (bytecodealliance#6769)
  Ignore async_stack_size if async_support is disabled (bytecodealliance#6771)
  A bunch of minor cleanups (bytecodealliance#6767)
  Fix flaky tests in preview2 streams (bytecodealliance#6763)
  Refactor and simplify component trampolines (bytecodealliance#6751)
  Cranelift: Implement tail calls on riscv64 (bytecodealliance#6749)
  WASI Preview 2: rewrite streams and pollable implementation (bytecodealliance#6556)
  cranelift-wasm: Add support for translating Wasm tail calls to CLIF (bytecodealliance#6760)
  Cranelift: Get tail calls working on aarch64 (bytecodealliance#6723)
  Implement component model resources in Wasmtime (bytecodealliance#6691)
  ...

* Add a helper for writing stdin tests

* Test a use of preview2::stdio::Stdin on unix

* Abstract the stdin test, and apply it to tokio::stdin and worker_thread_stdin

* re-implement worker thread stdin with a watch

* poll_oneoff_stdio should work on windows now

* comments

* test: show that restarting

* reap tasks from AsyncReadStream and AsyncWriteStream when dropped

the tasks will exit on their own if the receiver drops, but this should
terminate them while they are awaiting on read/write.

* rewrite most of the asyncfd based stdin

this has still got at least one serious bug, noted with FIXME.
also has a bunch of changes which can be backed out because they were
chasing red herrings.

the major bug was that, for some inexplicable reason, i didn't actually
set the fd to nonblocking just prior to asyncfd creation. switching from
the fdflags.difference to fdflags.union operator fixed that bug.

* Refactor to avoid `as_mut` and `.0 .0`

* Rework the stdin implementation to hold the stream in a mutex

* Detect when the task backing stdin has exited

* Have the thread managing stdin exit when it encounters EOF

* Refactor the test to restart the runtime as well

* Format

prtest:full

* internal tokio runtime used for sync interfaces is now new_current_thread

* Remove println from test for stdout

* Remove unneeded `vec!`

---------

Co-authored-by: Pat Hickey <phickey@fastly.com>