RFR: 8279018: CRC calculation in CDS should not include _version and _head_size [v2]

[Ioi Lam]

On Tue, 21 Dec 2021 04:17:50 GMT, Yumin Qi <minqi at openjdk.org> wrote:

>> Please review the simple change for not including _version and _header_size in crc computation. These two fields are checked separately and they should not affect crc.
>> 
>> tests: tier1,tier4
>> 
>> Thanks
>> Yumin
>
> Yumin Qi has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Restore GenericCDSFileMapHeader data layout, change compute_crc instead, add code to WhiteBox to get versions instead of hard code

LGTM

-------------

Marked as reviewed by iklam (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6899