Update how exits are modeled in the C API (#5215)

Previously extracting an exit code was only possibly on a `wasm_trap_t`
which will never successfully have an exit code on it, so the exit code
extractor is moved over to `wasmtime_error_t`. Additionally extracting a
wasm trace from a `wasmtime_error_t` is added since traces happen on
both traps and errors now.

crates/c-api/include/wasmtime/error.h

@@ -48,6 +48,24 @@ WASM_API_EXTERN void wasmtime_error_message(
     wasm_name_t *message
 );
 
+/**
+ * \brief Attempts to extract a WASI-specific exit status from this error.
+ *
+ * Returns `true` if the error is a WASI "exit" trap and has a return status.
+ * If `true` is returned then the exit status is returned through the `status`
+ * pointer. If `false` is returned then this is not a wasi exit trap.
+ */
+WASM_API_EXTERN bool wasmtime_error_exit_status(const wasmtime_error_t*, int *status);
+
+/**
+ * \brief Attempts to extract a WebAssembly trace from this error.
+ *
+ * This is similar to #wasm_trap_trace except that it takes a #wasmtime_error_t
+ * as input. The `out` argument will be filled in with the wasm trace, if
+ * present.
+ */
+WASM_API_EXTERN void wasmtime_error_wasm_trace(const wasmtime_error_t*, wasm_frame_vec_t *out);
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif

crates/c-api/include/wasmtime/trap.h

@@ -69,15 +69,6 @@ WASM_API_EXTERN wasm_trap_t *wasmtime_trap_new(const char *msg, size_t msg_len);
  */
 WASM_API_EXTERN bool wasmtime_trap_code(const wasm_trap_t*, wasmtime_trap_code_t *code);
 
-/**
- * \brief Attempts to extract a WASI-specific exit status from this trap.
- *
- * Returns `true` if the trap is a WASI "exit" trap and has a return status. If
- * `true` is returned then the exit status is returned through the `status`
- * pointer. If `false` is returned then this is not a wasi exit trap.
- */
-WASM_API_EXTERN bool wasmtime_trap_exit_status(const wasm_trap_t*, int *status);
-
 /**
  * \brief Returns a human-readable name for this frame's function.
  *