RFR: 8287101: CDS should check for file truncation for all regions

[Calvin Cheung]

On Thu, 2 Jun 2022 22:36:49 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> Currently, only the `last_valid_region` is checked for file truncation for a CDS archive. If serial GC is used, file truncation is not detected because the `last_valid_region` is empty so `si->file_offset() == 0`. This change is for checking file truncation for all regions.
>> 
>> Also add a test which truncates at the end of the file to trigger the "The shared archive file has been truncated." error.
>> 
>> Testing: tiers 1 and 2, also ran the test case with -XX:+UseSerialGC.
>
> Looks good.

Thanks @iklam and @coleenp for the review.

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PR: https://git.openjdk.java.net/jdk/pull/9004