don't limit the number of FDs on Windows when autoscaling

sys_not_unix.go

@@ -1,4 +1,4 @@
-//go:build !linux && !darwin
+//go:build !linux && !darwin && !windows
 
 package rcmgr
 

sys_windows.go

@@ -0,0 +1,11 @@
+//go:build windows
+
+package rcmgr
+
+import (
+	"math"
+)
+
+func getNumFDs() int {
+	return math.MaxInt
+}