Make  GCToOSInterface::FlushProcessWriteBuffers use MEMBARRIER_CMD_PRIVATE_EXPEDITED if available (#23778)
Make  GCToOSInterface::FlushProcessWriteBuffers use MEMBARRIER_CMD_PRIVATE_EXPEDITED if available (#23778)

Basically a port of  https://github.com/dotnet/coreclr/pull/20949   to  GCToOSInterface
wtgodbe/coreclr,cshung/coreclr,poizan42/coreclr,wtgodbe/coreclr,poizan42/coreclr,wtgodbe/coreclr,krk/coreclr,poizan42/coreclr,cshung/coreclr,cshung/coreclr,cshung/coreclr,wtgodbe/coreclr,krk/coreclr,poizan42/coreclr,krk/coreclr,krk/coreclr,poizan42/coreclr,cshung/coreclr,cshung/coreclr,krk/coreclr,wtgodbe/coreclr,poizan42/coreclr,krk/coreclr,wtgodbe/coreclr