sys/windows: remove miri hack that is only needed for win7

Author: RalfJung

library/std/src/sys/pal/windows/c.rs

@@ -177,7 +177,6 @@ extern "system" {
 
 #[cfg(target_vendor = "win7")]
 compat_fn_optional! {
-    crate::sys::compat::load_synch_functions();
     pub fn WaitOnAddress(
         address: *const c_void,
         compareaddress: *const c_void,

library/std/src/sys/pal/windows/compat.rs

@@ -198,11 +198,10 @@ macro_rules! compat_fn_with_fallback {
 
 /// Optionally loaded functions.
 ///
-/// Actual loading of the function defers to $load_functions.
+/// Relies on the functions being pre-loaded elsewhere.
 #[cfg(target_vendor = "win7")]
 macro_rules! compat_fn_optional {
-    ($load_functions:expr;
-    $(
+    ($(
         $(#[$meta:meta])*
         $vis:vis fn $symbol:ident($($argname:ident: $argtype:ty),*) $(-> $rettype:ty)?;
     )+) => (
@@ -221,9 +220,6 @@ macro_rules! compat_fn_optional {
 
                 #[inline(always)]
                 pub fn option() -> Option<F> {
-                    // Miri does not understand the way we do preloading
-                    // therefore load the function here instead.
-                    #[cfg(miri)] $load_functions;
                     NonNull::new(PTR.load(Ordering::Relaxed)).map(|f| unsafe { mem::transmute(f) })
                 }
             }