wiggle: make wasmtime a mandatory dep, get rid of own Trap enum (#5137)

* wiggle: no longer need to guard wasmtime integration behind a feature

this existed so we could use wiggle in lucet, but lucet is long EOL

* replace wiggle::Trap with wiggle::wasmtime_crate::Trap

* wiggle tests: unwrap traps because we cant assert_eq on them

* wasi-common: emit a wasmtime::Trap instead of a wiggle::Trap

formally add a dependency on wasmtime here to make it obvious, though
we do now have a transitive one via wiggle no matter what (and therefore
can get rid of the default-features=false on the wiggle dep)

* wasi-nn: use wasmtime::Trap instead of wiggle::Trap

there's no way the implementation of this func is actually
a good idea, it will panic the host process on any error,
but I'll ask @mtr to fix that

* wiggle test-helpers examples: fixes

* wasi-common cant cross compile to wasm32-unknown-emscripten anymore

this was originally for the WASI polyfill for web targets. Those days
are way behind us now.

* wasmtime wont compile for armv7-unknown-linux-gnueabihf either

crates/wasi-common/src/snapshots/preview_0.rs

@@ -28,10 +28,10 @@ impl wiggle::GuestErrorType for types::Errno {
 }
 
 impl types::UserErrorConversion for WasiCtx {
-    fn errno_from_error(&mut self, e: Error) -> Result<types::Errno, wiggle::Trap> {
+    fn errno_from_error(&mut self, e: Error) -> Result<types::Errno, wasmtime::Trap> {
         debug!("Error: {:?}", e);
         e.try_into()
-            .map_err(|e| wiggle::Trap::String(format!("{:?}", e)))
+            .map_err(|e| wasmtime::Trap::new(format!("{:?}", e)))
     }
 }
 
@@ -932,7 +932,7 @@ impl wasi_unstable::WasiUnstable for WasiCtx {
         Ok(num_results.try_into().expect("results fit into memory"))
     }
 
-    async fn proc_exit(&mut self, status: types::Exitcode) -> wiggle::Trap {
+    async fn proc_exit(&mut self, status: types::Exitcode) -> wasmtime::Trap {
         Snapshot1::proc_exit(self, status).await
     }
 

crates/wasi-common/src/snapshots/preview_1.rs

@@ -35,10 +35,10 @@ impl wiggle::GuestErrorType for types::Errno {
 }
 
 impl types::UserErrorConversion for WasiCtx {
-    fn errno_from_error(&mut self, e: Error) -> Result<types::Errno, wiggle::Trap> {
+    fn errno_from_error(&mut self, e: Error) -> Result<types::Errno, wasmtime::Trap> {
         debug!("Error: {:?}", e);
         e.try_into()
-            .map_err(|e| wiggle::Trap::String(format!("{:?}", e)))
+            .map_err(|e| wasmtime::Trap::new(format!("{:?}", e)))
     }
 }
 
@@ -1214,12 +1214,12 @@ impl wasi_snapshot_preview1::WasiSnapshotPreview1 for WasiCtx {
         Ok(num_results.try_into().expect("results fit into memory"))
     }
 
-    async fn proc_exit(&mut self, status: types::Exitcode) -> wiggle::Trap {
+    async fn proc_exit(&mut self, status: types::Exitcode) -> wasmtime::Trap {
         // Check that the status is within WASI's range.
         if status < 126 {
-            wiggle::Trap::I32Exit(status as i32)
+            wasmtime::Trap::i32_exit(status as i32)
         } else {
-            wiggle::Trap::String("exit with invalid exit status outside of [0..126)".to_owned())
+            wasmtime::Trap::new("exit with invalid exit status outside of [0..126)")
         }
     }