Fix alignment errors in hashtable fuzzer

Fix alignment errors in hashtable fuzzer

we extract several values (uint16_t and uint64_t from the fuzzer buff
passed in, but they weren't aligned on 2 and 8 byte boundaries.  Adjust
the fuzzer to memcpy data to the target variables to avoid unalignment
issues

Fixes #24272

Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
(Merged from https://github.com/openssl/openssl/pull/24276)