Avoid unnecessary slice allocation in usermem.BytesIO.blocksFromAddrRanges().
Avoid unnecessary slice allocation in usermem.BytesIO.blocksFromAddrRanges().

PiperOrigin-RevId: 280507239

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor