RFR: 8304144: G1: Remove unnecessary is_survivor check in G1ClearCardTableTask

[Y. Srinivas Ramakrishna]

On Tue, 14 Mar 2023 15:02:57 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Simple removing redundant check.
> 
> Test: tier1-6

@tschatzl & @albertnetymk : 

I'd suggest adding an assert that the region for which cards are being cleared is not a survivor region, with a comment to that effect. That would safely take care of both of your intentions/comments here.

Otherwise looks good.

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Changes requested by ysr (Reviewer).

PR: https://git.openjdk.org/jdk/pull/13023