https://pastebin.com/CmnzwUFN

The key idea is to avoid using 16 byte NEON and use 8 byte NEON which has lower latency for BitMask::Match. Even though 16 byte NEON achieves higher throughput, in SwissMap it's very important to catch these Matches with low latency as probing on average happens at most once.

I also introduced NonIterableMask as ARM has really great cbnz instructions and additional AND on scalar mask had 1 extra latency cycle

PiperOrigin-RevId: 453216147
Change-Id: I842c50d323954f8383ae156491232ced55aacb78