disable isolation check for QueryPerformanceFrequency

Author: pvdrz

src/shims/time.rs

@@ -236,7 +236,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         let this = self.eval_context_mut();
 
         this.assert_target_os("windows", "QueryPerformanceFrequency");
-        this.check_no_isolation("`QueryPerformanceFrequency`")?;
 
         // Retrieves the frequency of the hardware performance counter.
         // The frequency of the performance counter is fixed at system boot and