## What changes were proposed in this pull request?
For MemoryMode.OFF_HEAP, Unsafe.getInt etc. are used with no restriction.
However, the Oracle implementation uses these methods only if the class variable unaligned (commented as "Cached unaligned-access capability") is true, which seems to be calculated whether the architecture is i386, x86, amd64, or x86_64.
I think we should perform similar check for the use of Unsafe.
Reference: https://github.com/netty/netty/blob/4.1/common/src/main/java/io/netty/util/internal/PlatformDependent0.java#L112
## How was this patch tested?
Unit test suite
Author: tedyu <yuzhihong@gmail.com>
Closes#11943 from tedyu/master.
e1f6845391