net-utils: consume port range

[t-nelson]

Problem

#611 attempts to introduce binding sockets with SO_REUSEPORT. this breaks some brittle port allocation logic that assumes bind() with fail for unavailable ports. for those with SO_REUSEPORT set it now succeeds, leading to duplicate allocations.

Summary of Changes

rework bind*in_range helpers from solana_net_utils to work off a shared iterator so ports that are successfully bound are not retried later