Preserve full native stack traces in errors (#823)

* Preserve full native stack traces in errors

This commit builds on #759 by performing a few refactorings:

* The `backtrace` crate is updated to 0.3.42 which incorporates the
  Windows-specific stack-walking code, so that's no longer needed.
* A full `backtrace::Backtrace` type is held in a trap at all times.
* The trap structures in the `wasmtime-*` internal crates were
  refactored a bit to preserve more information and deal with raw
  values rather than converting between various types and strings.
* The `wasmtime::Trap` type has been updated with these various changes.

Eventually I think we'll want to likely render full stack traces (and/or
partial wasm ones) into error messages, but for now that's left as-is
and we can always improve it later. I suspect the most relevant thing we
need to do is to implement function name symbolication for wasm
functions first, and then afterwards we can incorporate native function
names!

* Fix some test suite assertions

crates/jit/src/action.rs

@@ -6,10 +6,7 @@ use std::cmp::max;
 use std::{fmt, mem, ptr, slice};
 use thiserror::Error;
 use wasmtime_environ::ir;
-use wasmtime_runtime::{
-    wasmtime_call_trampoline, Backtrace, Export, InstanceHandle, TrapMessageAndStack,
-    VMInvokeArgument,
-};
+use wasmtime_runtime::{wasmtime_call_trampoline, Export, InstanceHandle, Trap, VMInvokeArgument};
 
 /// A runtime value.
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
@@ -103,12 +100,7 @@ pub enum ActionOutcome {
     },
 
     /// A trap occurred while the action was executing.
-    Trapped {
-        /// The trap message.
-        message: String,
-        /// Backtrace.
-        trace: Backtrace,
-    },
+    Trapped(Trap),
 }
 
 /// An error detected while invoking a wasm function or reading a wasm global.
@@ -196,7 +188,7 @@ pub fn invoke(
     compiler.publish_compiled_code();
 
     // Call the trampoline.
-    if let Err(TrapMessageAndStack(message, trace)) = unsafe {
+    if let Err(trap) = unsafe {
         instance.with_signals_on(|| {
             wasmtime_call_trampoline(
                 callee_vmctx,
@@ -205,7 +197,7 @@ pub fn invoke(
             )
         })
     } {
-        return Ok(ActionOutcome::Trapped { message, trace });
+        return Ok(ActionOutcome::Trapped(trap));
     }
 
     // Load the return values out of `values_vec`.