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/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.
  *