Summary

According to the discuss in #27445, we can use UseUnalignedAccesses and !UseUnalignedAccesses to cover the AvoidUnalignedAccesses Flag, so I Remove the AvoidUnalignedAccesses Flag in this patch

Problem

There is no need for AvoidUnalignedAccesses Flag since the UseUnalignedAccesses can cover the same situations.

Solution

Replace AvoidUnalignedAccesses with !UseUnalignedAccesses and remove the flag in globals_riscv.hpp

Specification

we mainly replace the AvoidUnalignedAccesses with !UseUnalignedAccesses, Except for that, we should make sure that the UseUnalignedAccesses flag has been properly assigned before use, so we move the default UseUnalignedAccesses set top of the other use

https://github.com/openjdk/jdk/pull/27510