LongFileTime.ToDateTimeOffset perf (dotnet/corefx#28129)

Commit migrated from https://github.com/dotnet/corefx/commit/e2c62e0d283bf6479684db9cfb081ef0bcacf05f

src/libraries/Common/src/Interop/Windows/Interop.LongFileTime.cs

@@ -23,6 +23,6 @@ internal struct LongFileTime
         internal long TicksSince1601;
 #pragma warning restore CS0649
 
-        internal DateTimeOffset ToDateTimeOffset() => DateTimeOffset.FromFileTime(TicksSince1601);
+        internal DateTimeOffset ToDateTimeOffset() => new DateTimeOffset(DateTime.FromFileTimeUtc(TicksSince1601));
     }
 }