RFR: 8237521: Memory Access API fixes for 32-bit

[Nick Gasson]

Hi,

Bug: https://bugs.openjdk.java.net/browse/JDK-8237521
Webrev: http://cr.openjdk.java.net/~ngasson/8237521/webrev.01/

This is a follow-up to JDK-8236634 which just contained changes to the 
tests to make them build/pass on 32-bit systems for JDK 14. This patch 
removes the test workarounds and fixes two things to make them pass:

* In Unsafe_AllocateMemory0 handle the case where the aligned-up size 
overflows a 32-bit size_t and throw an OutOfMemoryError instead of 
calling os::malloc(0).

* Change the value of Utils.MAX_ALIGN from 16 to 8 on 32-bit systems, as 
malloc can return addresses that are only 8-byte aligned.

Tested jdk_foreign on x86_32, arm32, aarch64, x86_64.


Thanks,
Nick