[wasi-common]: winx now returns io::Error directly (#1243)

* Winx now returns io::Error

This commit is a spiritual follower of #1242 in the sense that it
adjusts `winx` to also return `io::Error` directly rather than
tossing a custom error type here and there.

* Adapt wasi-common to changes in winx

* Run cargo fmt

* Swap overly big map_err with explicit match

crates/wasi-common/winx/src/time.rs

@@ -1,7 +1,8 @@
 use cvt::cvt;
+use std::io::Result;
 use winapi::um::{profileapi::QueryPerformanceFrequency, winnt::LARGE_INTEGER};
 
-pub fn perf_counter_frequency() -> std::io::Result<u64> {
+pub fn perf_counter_frequency() -> Result<u64> {
     unsafe {
         let mut frequency: LARGE_INTEGER = std::mem::zeroed();
         cvt(QueryPerformanceFrequency(&mut frequency))?;