[crac] RFR: Support updating MANAGEABLE JVM options during restore [v2]

[Anton Kozlov]

On Fri, 28 Apr 2023 15:07:41 GMT, Anton Kozlov <akozlov at openjdk.org> wrote:

>> Radim Vansa has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Use RESTORE_SETTABLE on JVM flags
>>   
>>   * Fail early when using non settable flags
>>   * CracBuilder fix: don't use classpath during restore
>
> src/hotspot/os/linux/os_linux.cpp line 6579:
> 
>> 6577:     }
>> 6578:     if (result != JVMFlag::Error::SUCCESS) {
>> 6579:       warning("VM Option '%s' cannot be changed, ignoring: %s",
> 
> A significant set of options cannot be set on restore at the moment, so it will be even better to highlight they don't have effect and produce an error. It may be useful to revert back to warning (with e.g. an option), but by default it should be disabled (leading to the error)

The place can be `guarantee(result == JVMFlag::Error::SUCCESS, "...")` since the possibility was checked earlier.

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PR Review Comment: https://git.openjdk.org/crac/pull/61#discussion_r1183558035