Merge #2807

2807: Run Wasm code on a separate stack r=Amanieu a=Amanieu

This uses the [corosensei](https://crates.io/crates/corosensei) crate to
run Wasm code on a separate stack from the main thread stack.

In trap handlers for stack overflows and memory out of bounds accesses,
we can now check whether we are executing on the Wasm stack and reset
execution back to the main thread stack when returning from the trap
handler.

When Wasm code needs to perform an operation which may modify internal
data structures (e.g. growing a memory) then execution must switch back
to the main thread stack using on_host_stack. This is necessary to avoid
leaving internal data structure in an inconsistent state when a stack
overflow happens.

In the future, this can also be used to suspend execution of a Wasm
module (#1127) by modeling it as an async function call.

Fixes #2757
Fixes #2562


Co-authored-by: Amanieu d'Antras <amanieu@gmail.com>

.github/workflows/test-sys.yaml

@@ -226,7 +226,7 @@ jobs:
       - name: Install Nightly Rust for Headless
         uses: actions-rs/toolchain@v1
         with:
-          toolchain: 'nightly-2021-11-01'
+          toolchain: 'nightly-2022-02-08'
           target: ${{ matrix.target }}
           override: true
           components: "rust-src"