Use Drop instead of destroy() for locks.

library/std/src/sys/windows/locks/condvar.rs

@@ -51,8 +51,4 @@ impl Condvar {
     pub unsafe fn notify_all(&self) {
         c::WakeAllConditionVariable(self.inner.get())
     }
-
-    pub unsafe fn destroy(&self) {
-        // ...
-    }
 }

library/std/src/sys/windows/locks/mutex.rs

@@ -53,9 +53,4 @@ impl Mutex {
     pub unsafe fn unlock(&self) {
         c::ReleaseSRWLockExclusive(raw(self));
     }
-
-    #[inline]
-    pub unsafe fn destroy(&self) {
-        // SRWLock does not need to be destroyed.
-    }
 }

library/std/src/sys/windows/locks/rwlock.rs

@@ -38,9 +38,4 @@ impl RwLock {
     pub unsafe fn write_unlock(&self) {
         c::ReleaseSRWLockExclusive(self.inner.get())
     }
-
-    #[inline]
-    pub unsafe fn destroy(&self) {
-        // ...
-    }
 }